Mattsd:
I have owned, shot, and carried concealed the P10, P12, P13, and P14. Here is my .02.
The P10 does not work out of the box. Two trips back to Para's service shop and three to my local gunsmith before it worked right. Terrible service and customer service. I have now put about 500 rounds through it since the last malfunction, but I still do not trust it unless I absolutely have to go very small.
The P12 (LW and Limited) are both great and worked just fine out of the box. Never had a malfunction in over 3000 rounds through the two pistols. The mag well is too short for large hands. That is easily remedied by the addition of the S&A mainspring housing/mag guide, since the stock plastic mainspring housing needs to be replaced anyway (along with the plastic mag release button). Get the Limited and add the mag guide, mag release, and night sights and it is ready for concealed carry. The alloy is great if you are going to carry very much, but costs more to upgrade to a good package and has a bit more felt recoil (less than the LW Officer's Model).
The P13 Limited works great as well in over 1000 rounds. The only issue is that the Limited comes with the big, adjustable Bomar type sights, which are uncomfortable as hell to carry against your body. Add the same mods as above, and move from the Officer's Model sized P12 to the Commander sized P13. Again, consider the lightweight if carrying very much.
The P14 alloy and Limited in .45 ACP and .40 S&W work well after several thousand rounds. The same considerations as above apply, and the P14 is a full sized frame. That can make it a bit difficult to conceal and it is bulky to carry concealed.
Of all of them, my favorite for CCW is the lightweight P12 with several additional mods, or the P13 Limited frame with a P12 Limited slide on it. Just my .02, YMMV.
Hope this helps.