The LW Champion Operator is awesome.
Mine shot 100% out of the gate (until I rotated in some non-wilson magazines)
It had an out of spec slide stop that was dragging the slide ever so slightly. It was enough tension/drag to cause some magazines not to lock back on last round (The ones with the duck lip folded metal follower like some Chip McCormick models).
If you put the empty magazine in the gun and pull the slide back, you could see the slide stop holding down the follower.
Most magazines worked fine, but a couple I had did not.
I replaced the slide stop with a 10-8 one and no more issues. I also filed the slide track on the stop a touch wider and the factory stop functioned fine after that.
I also have a Side Nightmare Carry. It too had an out of spec slide stop that prevented some magazines from locking back. The lobe that gets pushed up by the follower was too short and would cause the follower to jump past and not lock the slide open on last round. It really only happened on "hot" rounds (Ranger-T) but it was consistent. When it happened, if you pulled the slide back, you could see the follower was pushed over to the right. Again, didn't happen with Wilson magazines, just a few others that I had.
Again, I replaced the slide stop with a 10-8.
Other than that, it too has worked great. I really like the round butt of the Sig and it handles great. Both guns are nicely accurate.
If I had to keep just one, it's be the LW Operator though. It's a great shooting gun, I like the aluminum frame and rail.
If I were to change the LW Operator to make it better, I'd have the front strap checkered and the grip bob tailed.