The Sig 716 Patrol was my first SIG rifle. It has had zero problems. Quite a bit more accurate than the FAL, especially since I put in a Hogan single stage trigger. Scoped it with a Vortex Viper PST 1-4x24.
The 556XI Russian is a second gen. Was looking to get a BMW of the AK's. The first 300 rounds, it had about a 10% FTF, FTE rate, regardless of magazine or ammo. Sent it back to Sig and got it back in about two weeks. The next 400 rounds had one FTE that I would attribute to 60's era Chinese surplus. Really like the gun but need to fire it some more. Long heavy trigger that will be replaced and will replace the safety selector also. Put a Viper Spitfire on it.
The MCX was my Christmas present to myself. Mounted a Burris 1-4x24 Fullfield TAC 30 on it. About 400 rounds of 55gr. reloads and British SS109. No problems except for, it did not like one H&K Mag, with failures to feed. May just need to adjust it a little but since it runs well in the M4 I just moved it over to its kit.Have never tried Wolf in .556 . Really like the ergos, but wrapped para cord on the top of the skeleton stock. Like the ability to side fold it and put in the Hazard 4 pack. Low profile but still too tactical looking. Just put in a ALG defense trigger to replace the 9lb. OEM.
Been wanting to try some different piston guns other than all the D.I. AR's that I built. Generally satisfied with the SIG's and like the sexy style.