I only have one, a M90 Rattlesnake that I got to try some of the new Lumens Factory stuff in. Quality is very good, overall. No complaints about the fit/finish. The clickie tailcap design sucks, with the switch being held in place with a bead of epoxy, apparently. My switch popped out the front of the tailcap the first time I clicked it without batteries on the other side to hold it in place. Still works fine as long as its only clicked in actual use, but I'm supposed to have a replacement on the way.
I've been using some of Wolf-Eyes' LAs for awhile in Surefires, and the "poor man's Surefires" have better beams than comparable ones from SF, whiter, with fuller hotspots, brighter spill, more overall output, plus the LAs are cheaper. I love their lamp assemblies.
I don't think anything can touch them for the money. If it weren't for the fact that my favorite lights are some of the CombatGrip models, I probably wouldn't give SF a second look since discovering Wolf-Eyes.
If I buy another light anytime soon, I'm sure it will be another WE. The availability of larger reflectors without having to go to a turbohead(not to mention the Lumens Factory D36 offerings), and 18mm tubes are a big selling point to me.