Yes. I only have time to surf tonight, but in short - I'm keeping my Sig RX.....likely getting rid of the M&P. The Sig shoots better, feels better, has a better stock trigger (apex upgrades on either don't count) and the "320" factor of making different lego guns puts it over the top.
I don't have the Sig RX, but do have the compact and Subcompact version. I have never shot the MP but can tell you the stock triggers on the Subcompact and Compact are a bit heavy. Comparing that to a MP 2.0, I like the 2.0 a lot better because the trigger is 10x better than both Sigs.
I do love my Sig P320's but it's only for a defensive carry pistol. When I want to target shoot, nothing beats a Walther PPQ
I own both the Sig P320 Compact and Subcompact and I shoot both equally as well. The Shield without grip tape not as well but with grip tape shoot just as well. However, I like the Shield .45ACP better than both because it is more accurate than the 9mm rounds.
SIG's P320 subcompact is only slightly larger than the Shield, and it carries 12 rounds of 9mm or 10 rounds of .40 cal. Here is a link: P320 Nitron Subcompact