I absolutly love my P290. I have owned several pocket pistols and it is head and shoulders the best one on the market. The lcp weighs 11oz and the 290 weighs barely 20oz, but volumetrically there isn't much difference in them at all. You can see pics of them side by side on YouTube. I don't use a pocket holster. I have been carrying pocket pistols for many years and the trigger is strong enough that a holster isn't needed. You are right I would lube any Sig well. If were you I would absolutly buy the 290. It comes down to the fact that they are both small enough to carry anywhere but you have 9mm vs .380 and the 9mm especially with 115+p Corbon pure copper DPX's are a major step up from the LCP. The 290 has Siglite night sights standard and will easily run any size, type and brand ammo you feed it! To me the pocket pistol is the most important gun you own because it's the one that's always with you. So get the best! In short buy the 290 I guarentee you will not regret it!!
I saw you commented on carrying the P290 in your pocket. is it holstered? With what?
How does it compare sizewise in the pocket vs the LCP?
I am VERY interested in the P290. There's a first edition at my LGS. Is the latest version better? I own no sigs. My neighbors are cops that all carry P226. They love them, but say "they don't run dry, gotta lube".