I can study all time and still won't know what I'll need down the road The only thing that I truly worry about is how bad buying a five year old model really is. Nobody would buy a 5 years old computer or TV unless it was at a massive discount. Maybe scopes move slower, that's why I made this thread. If it wasn't for that concern, I would have bought the DS1054Z already. I know the Rigol is great for my immediate use cases and it's among the lowest cost models. The more expensive alternatives sure look 'cool', but don't really have anything that I truly need and I'd rather not spend more. I would happily wait a while longer if there was an updated model around the corner that would deliver more for the same price... Looks like that's either not the case or impossible to say.
You don't know your future use and neither do we. And, trust me, there is always a better scope for a bunch more money.
It took 4 years to get the Rigol firmware fixed and, at this point, the DS1054Z is pretty well bug free. Not design compromise free... I haven't followed along with the Siglent but it's pretty much assured that no scope comes to market bug free. Does that make older scopes better in the sense that the bugs have been ironed out? Search the Test Equipment forum to see what the latest story is on Siglent.
Amazon prices (US)
DS1054X $379 <= 4 channel can be unlocked to 100 MHz
SDS1202X-E $379 <= 2 channel 200 MHz
SDS1104X-E $499 <= 4 channel 100 MHz can be unlocked to 200 MHz
SDS1204X-E $759 <= 4 channel 200 MHz
Given the choices above, I would buy the SDS1104X-E with the intention of unlocking 200 MHz. These days there is little point in buying a 2 channel scope because, among other things, debugging an SPI bus is easier with 4 channels (CS', CLK, MISO, MOSI). That is precisely the reason I bought the DS1054Z - I wanted features and channels. I already had bandwidth with my Tektronix 485 (350 MHz, 2 channel).
In any event, prices and budget will be the deciding issues. I would like to buy the SDS1204X-E (so I don't have to play unlock games) but it is simply not in my future based simply on cost. The extra 100 MHz is great over the DS1054Z but I don't have a need at the moment and when I do, maybe the 485 will deal with it.