I should mention that the RTB2000 has one major limitation which draw me away from it quickly after realizing it: while it says it allows two decoders at the same time, this is cheated, as each data directions counts at one decoder (Rx+Tx at RS232=2 decoders). I know no other manufacturer counting decoder this way - for all other I know, one decoder is always a full duplex decoder.
In fact this made me really angry when realizing it, as it just an intentional crippling to sell more of the RTB3000 series scopes. Without this limitation I would have kept my RTB2004.
Examples: you cannot work e.g. on something with two SPI devices at the SPI bus as you would need 2x MISO (one active on CS1 the other on CS2), 1xMOSI which counts as 3 decoders.
Or working on a MCP2515 CAN controller: here would would need to see SPI MOSI (first decoder) MISO (second decoder) and CAN (third decoder).
Or think of a system with RS232 and I2C- you would need Rx, TX, I2C = 3 decoders
or RS232 and SPI: 4 decoders needed.
or 2 SPI devices on the SPI bus: 4 decoders needed
All other manufacturers (I know) will only need 2 decoder for the above.
Thus, for some hobbyists this limitation might be OK, but with with higher requirements these limitation can quickly be a problem.
Even the lowest series of Siglent, Rigol, Keysight (I assume even the 1000 series, but I don't know) all have at least 2 full duplex decoder - thus no problem with all these examples above; the RTB2000 can't (RTB3000 series can, so you might take a closer look there).
If you are working a lot on digital projects, think what you might need now and in the future.