I have both the P290RS and the Shield. Just like so many others before me have said, the trigger pull is quite long for the Sig, but with practice you become very familiar with the pull and it is quite smooth. I like the Shield mainly because I have smaller hands and even though it is only 0.06" thinner than the 290, it is sculpted at the top of the frame that makes it feel like its paper thin. My wife has a G26 and she said she likes the way the Shield feels better than the Glock too (now I just have to find another for her). For the money, at least what I paid ($550) for the P290RS, Sig night sights, and laser it is a fantastic deal for the money. Sig quality it still excellent, just as good as my 226 and 229s. With that said, I carry the Shield and will until I find a reason not to anymore. Lack of night sights a big deal? Nope. Safety? Don't have to use it just because its there.

Good luck with your choice, but having both won't kill you if you can't decide. =)