I had an OT for a year and I hated it. Everything is a pain with it. Organizing samples sucked, I never got a good workflow. When I finally did wrap my head somewhat around the OS I was consistently disappointed with everything I tried to do. I tried to use it as a mixer for my other live gear, it was a tone and volume sucker, lost all my overhead, it's a terrible mixer. I tried to use it as an effects processor, the effects are abysmally bad, like 90's digitech stompbox bad. Just garbage thin digital effects all around. Maybe I just had too high hopes for it,
The DT on the other hand I instantly could get music out of it, the effects are nothing special, but they're acceptable, certainly not as bad as the OT. Little things make a big difference, the button size and placement for one. It's much easier to program on big square buttons arranged in 8 over 8 than it is in a 16 straight across. It's just instantly more intuitive, much easier to make patterns with the sequencer laid out this way. The screen is a million times better, menu navigation feels simpler. The OT was needlessly complicated for my needs.
I honestly hated the OT I feel it was a half baked concept, or perhaps an overbaked concept, burnt to a crisp. I already like the DT better and I've only had it for three days. Of course there's some minor bugs to work out, and I'm really hoping they follow through with software on this one. THe OT still has some pretty significant bugs and it's years old. OT updates are vaporware at this point.