My opinion: take two!
I mean RTB is something you should have. For the things it miss then is Rigol or Siglent.
There is no such thing as a perfect oscillocope . Always it will miss something that others have.
Hence my solution
There is quite some truth there, and it is also the way I plan my purchases... Instead of trying to define the perfect instrument (and, if it exists, pay a fortune), get a good one, as good as you can afford and are willing to pay at that point in time. Then, over time you find out what needs are not yet fulfilled, and that might be filled in additional, complementary purchases. In the context of the scopes discussed here, these do not necessarily need to be 350MHz or 500MHz versions, which can keep the costs of additional purchases down quite a bit and make them good value for money. Also, this strategy stretches out investments over time and allows you to make better-informed choices based on well-identified needs (or desires...)
(In my case, I got the RTB and will never regret it...Later bought an SDS2000X Plus, which offers some nice complementary elements, and might also add an MSO5000, complementing my setup other dimensions (but fewer).
Yeah sounds good in theory but are you adding value by getting more of the same?
SDS2000X+, MSO5000 and RTB2000 are largely targeting same segment. While they are different, they are also similar in capabilities.. DSOX1204 is very entry level scope for those that want analog experience and are prepared to pay inflated prices for big name (nothing wrong with that, just pointing it out).
1400€(Siglent SDS2104X Plus)+1200€(Rigol MSO5104)+4000€ (R&S® RTB2K-COM4)+1200€ (Keysight DSOX1204A/70MHz) combined gets you to almost 8000€. That is all scopes except RTB2000 in basic configuration, without logic probes, or full bandwidth upgrades. With those it will easily reach 10000€
While doing that you don't have any scopes that go to 1 GHz, or 5GS/s or more, no larger screens, no active probes..
OTOH 8000€ range buys you Siglent 5000X, 6000A, R&S RTM3000 with full bundle, if you get a good deal you might buy MSOX3104T or similar, even some smaller LeCroys might be available.... All of these will take you one level up in bandwidth and capabilities.
I have several scopes but all of them have distinct features that are really not available in single scope. 3 Picoscopes: one deep memory MSO that is superb for decoding (25+ protocols and counting), one 16Bit with specifications no other scope has, and one that is 12bit 8 channel and is great for power applications. Combine that with Keysight MSOX3104T and SDS6000 and there is very little you cannot do. Only place to go is up in BW, really, and going really high end.
And having MSOX3104T and SDS6000 at the same time already shows redundancy: I rarely fire up MSOX3104T these days, only when I want to verify something or something specific that it has (like USB PD trigger/decode) that SDS6000 doesn't have currently.
Having several very different scopes (in class, bandwidth, capabilities) is a good thing. But I would rather have one 1GHz capable scope of higher class than 2 500MHz ones. Hard limitations you cannot work around: BW, memory depth, active probe support..
My opinion.