my experience is:
- prophet 6: sounds nice, with analog drive, lo-pass / hi-pass filter and more instant access to almost all necessary sound-editing parameters, so that's already something what you're looking for.
It has all six voices you can use in chord memory
The downside is it's smaller keyboard, it's more limited sound architecture and thus less possibilities / less modern or diverse sounds to be made than a REV2.
As far as I remember the knobs from the P6 are the same or at least the same size. So, as is the case with most DSI's: a small turn can result in bigger changes quite rapidly, so also with the prophet 6 you have to be carefull and more precise than on a moog.
- prophet REV 2: you can make it really sound nice, but asks for a little more work to program subtile modulations into it, so you can make it sound more 'vintage' or 'less precise'.
To obtain that more instant-tweaking approach with less menu diving, the key is to prepare some kind of a 'default' patch!
You can program some modulations routings you like to start from (for example, I use the Foot controller a lot for VCF freq, add a LFO to pitch via MOD wheel etc; another other LFO to VCF; setting up a delay or chorus FX already; prepare a basic ARP and glide setting; etc...). Then just save it somewhere and use it as a default patch to start from, each time you want to program a new sound.
Some downsides: for being the ultimate DSI analog workhorse, it just misses some additional options / user defined tweaks (independent sustain pedal for each layer in a splitted or stacked preset; hold function (also the case on Prophet 6 btw); independent pitch bend up/down assignment; limitation of chord memory to just 4 voices (even on a 16v); only 1 fx per A or B patch; no analog drive;...).
Also the rotary's don't always work fine and feel a little cheap, which can be frustrating at times! They don't turn fluidly all the time, and sometimes its hard to dial in the right setting quickly (especially the rotary's for oscillator semitone tuning).
But, the REV2 really is a very cool and versatile analog instrument with a lot more possibilities than the Prophet 6 has!
I can advice you to test the Prophet 6 by yourself, spend some time with it in shop and then decide if it's more your thing than the REV2.
Personally, I wouldn't sell the REV2 too soon.
I do hope DSI do some improvements on it though...