I've been seeing deals on the Pro12 module here and there for as little as $1600, making it cheaper than the Pro2 at $2000.
Pro12 lacks the sequencer which is a pretty big deal and as mentioned above, the LPF is Curtis based so will sound different. Of course, it's polyphonic which is the biggest difference...do you want a polysynth or not?
Paraphonic means that there is only one filter rather than one per oscillator. So you can play four notes at a time but filter articulation is more limited than in a true polyphonic synth. There's also only one oscillator per note vs. four per note in mono mode or in the Pro12.
I listened to Hatfield and the North at Rainbow. They were very wonderful and they made my heart a prisoner.