I had a P12 before which was amazing in every way except that the keybed felt clacky and loose. Like a cheap midi controller. I loved the synth but ended up selling the P12 for the module which I later sold to fund some purchases. Today I found a P12 keyboard that was lightly used at a store and the action was much quieter acoustically and much more pleasant feeling. We opened up a brand new P12 out of the box which had a higher serial # and it was the same clacky keybed I remembered. Both the salesperson and I noticed an immediate difference. I've taken the used model home and am loving the feel. It is still not quite as nice as the Prophet 6/OB6/Rev 2, but it's much better than any other P12 I have ever played in the area, and I have tried several to make sure I wasn't going nuts.
I also found that it was easier to control velocity on this particular P12 than on any other one I have tried. Not only with the P12, but with the Tetra and Prophet '08 I owned before, which had the same keybed.
The only way most P12s are let down IMO is by the action of the keys. If you love the synth but key feel is important to you, I'd recommend getting the module. It's much easier to get around on than it appears. As for me, this loaner P12 might just have to stay, because I don't know if I'll ever find another one quite like it.