I just wanted to say, I own one of these synths as well and I think it's a fantastic instrument and agree with the assessment here. I have tried the other DSI Prophet instruments and in comparing them, I think that the specific pros of this one are definitely its build quality/keyboard feel, its price (which was why I chose this one specifically), and its completeness (built-in effects and ability to both create awesome vintage sounds and do modern dubsteppy things).
What I particularly like about this instrument are the modulation options available with 4 frequency-controllable LFOs and the sound options available with all the built-in effects.
It feels very sturdy and complete, and works great for packing up and bringing to gigs.
I don't particularly like the location of everything, as mentioned here, and the pitch bend/mod wheels being up above the keys takes some getting used to.
Not mentioned here is my annoyance of that the factory presets, which cannot be overwritten, are actually quite good but are not sorted well. Having to remember specific patches isn't as fun for me as it could be if, say, I was playing jazz and had all the electric piano and organ-like sounds near each other. Not much of a problem since I usually end up filling all the banks of programmable memory in my synths with my own patches anyway, but it is something that I feel could be easily fixed.
But yeah, all in all, this is an awesome synth that I don't think anyone would regret buying.