I’m by no means knocking the LGU, I have never shot it, but on principle alone I think that’s why I prefer the LGV. No sliding port (easier to load), less mechanical points, rock solid barrel lockup, and I prefer the looks of it once you add the LDC. From what I have heard, accuracy is on par or negligible with the LGU. So, if I’m getting an underlever, it will be a TX and/or an HW97.
Agree with many of your points though I would say no barrel lockup is better than even the best barrel lockup. The cocking mechanism is the weakest area IMO but not a major issue in my mind. The trigger is a non-issue as mine is very nearly as good as the HW97 after some work. As noted, MY LGU is more accurate than both MY HW97 and MY LGV. Not by a large amount and the LGV is very close but it is a noticeable amount. Your experience could be different. Can't speak about the AA, they have excellent reputations but I would note Rambler's post above. Plenty of choices for all to make.