The little semi-autos like the P3AT are hard to beat when it comes to power:weight ratio. A P3AT, fully loaded (6+1), in a pocket holster, with a loaded spare mag, weighs 15.15 ounces. That's 13 rounds in a holster. An S&W 37, .38 special airweight, w/ 5 125gr hollowpoints, no holster, weighs in at 15.9 ounces. That's 5 rounds without a holster. Both were weighed on a kitchen scale right in front of me. There is probably some variation but that's the ball park. So in the semi-auto you get 8 more rounds and a holster while shaving nearly an ounce off the total weight and the whole thing looks like an oversized wallet in your pocket.
But... there are other legitimate issues. Five shots you can trust, even from a pocket (though I suspect that's not something you'd want to do in real life) or while the gun is pressed up against something, probably beats 13 shots if you are lucky. Also, the flat pistol shape may not conceal as naturally as the revolver (though I'm not sure I buy that... revolvers are very distinctive to my eyes).
With the probable exception of ultralight .357 revolvers (and that's speculation on my part... I've never actually fired one of those) none of these guns actually qualify as punishing in the recoil department. They kick more than the .25 and .22 variants but they probably won't leave you sore after visiting the range.