I've had both the Kel-Tec P3AT and the Ruger LCP. The only difference in function that I noticed was that the trigger guard in the P3AT was smaller than the LCP, and I'd have some painful range sessions with the P3AT (from my trigger finger hitting the front of the 'guard when firing). That trigger guard and my long fingers just didn't get along. Otherwise, the Ruger was prettier, but I don't know that was really better.
Another option you should consider is the Kahr .380. Kahr guns tend to have better triggers and handle recoil better than the other small guns.
I've since decided against .380 for self defense and now have a Kahr CM9 and KT PF9 in a pocket holster. The CM9 is more pleasant to shoot, but I haven't decided to drop the PF-9, yet.
Most of them can be unpleasant to shoot, unless you do something to reduce the recoil. I use KTADDONS grip material, and it makes a big difference on the PF-9; I haven't tried that on the CM9; may not need it.
I haven't tried the Ruger "copy" of the PF-9, yet.