I don't want to derail the thread with a comparison shootout,
So that's the commercials break then I guess?
No seriously, you're welcome Daniel.
but I feel obligated to chip in on a couple points for the Keysight scopes (bear with me)
Sure
- Keysight's capacitive touch screen vs WS3k resistive touch screen. Ask for a demo/loaner, you won't want a scope without it
I fully agree to try it on a loaner, because the difference is negligible. A capacitive touch screen is a big advantage on a tablet or a smartphone where modern operating systems use multitouch operations and gestures, however that isn't true for a scope where touch operation mostly consist of pointing at stuff and drawing a box.
At the moment, there's only one big brand scope which uses multi-touch and gestures, and that is the new LeCroy WaveRunner 8000. And this does have a capacitive touch screen.
Also, resistive touch screens have the advantage that they work well with gloves, which is a big advantage in environments where you're not supposed to touch the UUT with bare hands. There DSOX3kT's capacitive display is useless in these environments because it's capacitive screen doesn't work with gloves.
- Serial decoding is done in hardware, so it's stinkin fast (also we have more supported protocols)
You are right that the DSOX3k supports a larger number of protocols (the WS3000 does support the most widespread ones like UART/RS232, SPI, I2C, CAN, FlexRay while the DSOX3kT also supports I2S, MIL-1553, ARINC-429, LIN and SENT). Of course if you need one of these additional protocols and can't live with a cheap USB gizmo then the DSOX3000T is the only sensible option - and Keysight really charges a premium for that.
- Keysight FFT is hardware accelerated, can be signal gated, and has a peak search in the lister
First of all, the DSOX3000T's FFT only does a measly 64kpts while the WaveSurfer 3000 can process up to 1Mpts, that's 16 times the amount of data!
Also, you say "hardware accelerated", which usually means it's done through a dedicated ASIC. That isn't necessarily an advantage, though, because as we've seen especially in high-end scopes which through their high speed ADCs produce much more data than scopes like the DSOX3kT and WS3k, LeCroy's software-based X-Stream architecture handles large amounts of data a lot better than the "hardware accelerated" architectures from other manufacturers including Keysight.
- 3 year cal cycle vs 1 year cal cycle
I agree, it's an advantage if you need it. There's no technical reason why any modern scopes couldn't work on a 3yr cal cycle (they are all pretty stable these days) so I'd assume others including LeCroy will update to 3yrs as well, which means the days this is an advantage will very likely be numbered.
- Keysight acquisition modes (normal, peak detect, average, high resolution) vs WS3k with "normal" mode only & "ERES" as a math channel
As you say, on the DSOX (like pretty much any other scope) these are indeed acquisition modes while on LeCroy scopes they are math traces, but having them as acquisition mode is not an advantage, because it means that in any other mode than "normal" you lose all the actual acquisition data (they are destructive). On a LeCroy scope, where waveform-altering functionality is available as math trace, the original sampling data is retained. This has always been LeCroy's core design principle, and is the reason why LeCroy has been and still is the to-go brand for scientists when it comes to scope.
Also, the DSOX3kT, like pretty much any non-LeCroy scope (aside from some newer Siglents apparently, but god knows how good their implementation is), only offers the standard simple boxcar filter for its high resolution mode. ERES is a bit more sophisticated as it uses a linear phase FIR filter which avoids the various disadvantages of boxcar filtering (i.e. appearance of ringing) or the complete lack of controls over the filtering process.
Of course, things like ERES or using waveform-altering functionality as math traces while retaining the original sample data is much more processing and memory intensive, but the WS3000 seems to perform very well against simpler scopes like the DSOX3kT, despite having to process more data.
BTW, Averaging is available on the WS3k as well of course, again as a math trace so the original sample data is always retained.
Regarding Peak Detect (PD), you're right. The WS3k, like most LeCroy scopes, doesn't have Peak Detect acquisition mode.
This is very odd now. LeCroy already had Peak Detect in the 9354AM
They pretty much dropped PD in 1998 (the 9384C was one of the few scopes which had PD, and also the last one).
I too find it very odd that a WS3000 does not have Peak Detect. 
One can only imagine that it's been left out of the incorporated features on purpose, if indeed it is missing.
It is on purpose. PD was a crutch to overcome the very small sample memories of older digital scopes, allowing to sample at full sample rate for an extended amount of time by storing only the minima and maxima of a sampled group and thereby extending the time length that can be acquired. As it is an acquisition mode, it is destructive (i.e. you lose the original sample data). You also lose timing information (you know in which sample period the data points were acquired, but you don't know where in that period, i.e. at the beginning or the end).
These days, scopes come with reasonably large sample memories, which means even in normal mode you can run the scope at full sample rate for longer timbases. Also, modern scopes tend to come with a much larger sample rate to BW ratio (the 750Mhz WS3074 samples at 4GSa/s, the 1Ghz DSOX3104T at 5GSa/s), which means there is lots of room for the sample rate to drop without losing any details. With its 10Mpts memory, even the 750MHz WS3 can aquire a 5ms period at sufficient sample rate (2GSa/s). And the lower the analog bandwidth the further the sample rate can be dropped without losing detail.
Modern mid-range and higher scopes also have sophisticated trigger and analysis tools so that the scope can capture the important event at high sample rate instead of having to capture a longer sequence via PD. Of course most entry-level scopes lack such functionality, and PD can then help there.
Bottom line is that PD is not offered because it's destructive and because LeCroy scopes like the WS3000 have suitable alternative ways (i.e. WaveScan) of capturing events at high time resolution.
I know that some people will probably disagree (I remember some discussions with nctnico about PD), but despite using mostly Keysight scopes at work which all have PD, I can't remember when the last time was when I used it (I vaguely remember one time in the early 2000's with some Tek scope). That of course doesn't mean much, and I'd be interested to hear about specific scenarios where people believe PD is still required - bearing in mind we're talking about a mid-range scope here, not some simple $400 Rigol box.
- Keysight DVM and hardware frequency counter & totalizer vs N/A
That's incorrect. The WS3000 does have hardware frequency counter, and it has the DVM (which was a free addition a few months after release, and a free upgrade for all existing scopes)
- Keysight 1 knob set per channel vs multiplexed channel knobs
Yes. If that's really an advantage it's up to your individual preference. My WavePro 7300A has individual controls, and I'd wish it was multiplexed because it allowed me to change channel settings without having to move my hand.
I'd rather have the space spent on a larger and higher resolution screen
- and of course waveform update rate and zone trigger...
You're right with the waveform update rate of course (which is amazingly high for an entry-level scope). It's a nice marketing feature, but it's advantage in real-life is pretty limited, especially when compared to other scopes with decent trigger/analysis tools. Plus it comes at the price of very limited sample memory, which is a pretty big disadvantage.
But zone trigger, really? The WS3000 comes with WaveScan which can do zonal triggering and a lot more. The DSOX3kT doesn't even have anything similar, because that is only available for the Infiniium Series (InfiniiScan). And off course like pretty much everything at Keysight, it's a paid-for option
. And having InfiniiScan on my work DSO91304A and WaveScan on my WavePro 7300A at home, I have to say that InfiniiScan can't even do half of what WaveScan can do. Plus WaveScan is free (comes with all LeCroy mid-range and high-end scopes, and when it came out it was a free upgrade for existing scopes). Go figure.
Since we're talking features, how about LabNotebook? It's a tool to create test reports and document testing directly on the scope. As with WaveScan, it comes standard with every LeCroy mid-range and high-end scope, and that includes the WS3000. What does the DSOX offer to make documenting test series easier? Exactly, pretty much nothing.
Lastly, lets have a quick look at pricing
The 100MHz 2ch DSOX3012T starts at $3500 while the 200Mhz 2ch WS3022 starts at $3.300 (it's price went up, actually, it used to start at $3k) - LeCroy gives you 2x the BW and 2.5x the memory for $300 less (or comparing similar BW, the 200MHz DSOX3022T is already at $4170 - that's $870 more which could be spent on probes and other tools instead)
Let's have a look at the 500MHz variants:
WS3054: $7500 vs Keysight DSOX3054T: $11704 - that's $4200 difference! You could even buy the 750Mhz WS3074 ($9200) and save $2500 which can buy you probes and other stuff.
Actually, the 500Mhz DSXO3054T is even more expensive than the 1Ghz WaveSurfer 10 which is $10k - double the BW, up to 16Mpts/Ch, and even more serial decode options than the DSOX3kT has for $1700 less.
Just for completeness, Keysight wants a whooping $14525 for the 1GHz DSOX3104T
Which puts it quite close to the WaveRunner 8000 - a sophisticated high end scope with 20/40GSa/s, up to 128Mpts/Ch, multi-touch, and large-capacitative touch display (the 500Mhz 4ch variant starts at $14k, the 1Ghz variant is probably around $16k).
I'm not sure that the separate vertical controls, PD, the excessive update rate and a few more serial decode options are worth the large price premium, even less so when it comes at the cost of tiny sample memory, smaller screen, and lack of other functionality.
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