When I got the Rytm, after coming from the MDUW I was a little underwhelmed by the Rytm lack of sampling, lack of good and flexible sounding machine types, BUT really have to say that since the last 2 updates the Rytm now feels “mature” and complete - still needs some more machines to round it out, but I think these will come eventually.
So a lot of the stuff I loved about the MDUW is still absent on Rytm, and always will be, when the announcement came that this will be last MD run it was a no brainer to get another.
I think they compliment eachother well, I’d love for the MD sequencer to be brought up to date, but that is not going to happen, there is very little overlap soundwise and as @void said already you can sds samples across to Rytm (use closed loop, and don’t expect super speed, though still workable)
I honestly can’t say which I prefer, they are both awesome, just as the 808(md) and 909(rytm) are, but if I was forced to choose maybe I’d pick MD.