can't speak for any other models but I've got an RP80 and it's absolute sh!te... 40 preset effects and not a single good one amongst them and setting your own effects is such a pain in the arse it's not worth bothering. It lives in my charity shop box.
Oh - I forgot about those (and the RP50) !!!
RP1 was built like a tank. I've seen it described as "the Helix" of its day. However, as you describe, you really had to put some effort in to programming them to get the most out of it (same with the RP2000). Not something you could do "on the fly"!
The Valeton is excellent and I can be dialled into a sound literally in seconds. Which is why the RP2000 is now at the same status as your RP80 but it served me well for a number of years.