Wife has the LCR and I have the LCP, so we have the best of both of the LC-worlds.
First impression after CC-ing both of them in IWB holsters, and taking them both to the range and firing them side by side is this:
If I want it for primarily carry purposes, and it HAD to be able to go in any pocket, and the gun won't get a lot of range time, I'd get the LCP. It's smaller, thinner, a little easier to conceal, but it can bite a bit during shooting. I know my trigger finger was ready to call uncle after only 20 rounds or so.
If I know I'm going to be spending some time at the range with the gun, and was going to IWB carry more than pocket carry, I'd get the LCR. Shooting wise, that trigger is nice, and the composite construction has a lot of inherent dampening characteristics making it a much more comfortable gun to shoot. And only at the expense of being slightly larger, for me it's still a more comfortable IWB carry than the LCP due to the rounder edges.