Remember also that the Rigol 6000 does not have an AWG (can probably get for free now?) or mixed signal LA option should you need those in the future.
The Agilent has limited memory because they decided to integrate the memory onto the main ASIC chip to get the speed that scope is capable of.
The Rigol uses standard SDRAM chips, so they can get huge memory at lost cost, but at the expense of system speed.
Yes, the Rigol is a pretty quick scope too, but still not in the same league as the Agilent which does almost everything (serial decode, masking etc) in hardware.
Yes, the Agilent has a separate ASIC (and hence memory) for each two channel pair.
Also remember that the update rate is a max value that occurs at a sweet spot on the timebase. Use that huge sample memory on the Rigol and the update rate drops to bugger-all. See this post as an example, I expect the 6000 to scale similar:
https://www.eevblog.com/forum/product-reviews-photos-and-discussion/first-impressions-and-review-of-the-rigol-ds2072-ds2000-series-dso/msg160064/#msg160064The Agilent wins on support and firmware updates etc.
I've found the demo signals in the Agilent to be real handy is setting up complex triggers etc.
And the Agilent likely has better future options as it has a more flexible platform to implement new stuff.
Yes, the Rigol is better bang-per-buck, and kicks butt on the memory depth.
Don't know, tough call. If you value memory depth, go Rigol, otherwise I'd say the Agilent is nicer.
Wait until next week, there may possibly be a new option for you, but I'm not sure of the price range...
Dave.