I own a Shield and have shot the P290. I passed on the P290.

If you want a comparable sized Sig, check out the P938.
A bit smaller in all dimensions than the Shield (just a hair bigger than the p238 380), 16oz empty (as opposed to 19oz empty) and a single action trigger... Basically a mini 1911 9mm.

The 938's recoil is a bit snappier than the Shield (the Shield's recoil is about even with the G26) and costs about $650, as opposed to the Shield being about $400.

And yes... The Shield DOES have a different (and better) trigger than than the other M&Ps. I don't know where 'walkin trails' read that it was the same, but those articles/sites are greatly mistaken.