Purchased these two Sig's before I left for Afghanistan, so they are in the can't wait to shoot when I come back category. Now I'm a self admitted Sig-a-holic so both guns are Sig's obviously. Anyway, the first is the new Sig 556xi. It's their latest version of the 556 rifle, a modular system in that you can swap out the barrel for a .300 Blackout or bolt and barrel for 7.62x39. I probably won't do the AK round but will do the blackout, less expensive to do. My LGS got to shoot it at the SHOT show, loved it. They never push a product and they sell much higher end makers of AR's, AK's, etc than Sig so I trust their judgement.
The second is the Sig PM400 pistol. Now I already have an M400 and it has been rock solid, a great mid level AR15 IMO. I wanted a SBR AR but don't feel like waiting, paying the tax stamp, etc (I will eventually) so I opted for the PM400 with the stabilizing brace. It has the 11.5" barrel so some loss in velocity but IMO, it's for 300 yards or less.