I got myself in trouble the last time I waded into a thread like this, but where KISS is concerned I doubt I'd have to bow to anyone here with exception maybe to Scott in the length of time and intensity in which I've been a fan of the band. That being said, (and apropos of nothing) the fact that something came out of Gene's mouth is proof enough that it's probably a lie if not a gross under or over-exaggeration (if you need to guess which, just remember that the outcome always has to benefit KISS).
Alive is one of my top 5 albums of all time. If I could only take one KISS album onto that desert album, as much as I love the classic KISS lineup and albums (actually up to Creatures), Alive would be it. That being said, Alive is far less live than advertised. Guess what, so is almost every other 'live' album from that era. Not all, but most. So what. Alive II? Sorry, but side 4 is the most live side on that turd. Side 4 also makes up for the other three sides, so that's not a bad thing. Note to anyone who would argue over how live that album is: KISS didn't perform "Tomorrow and Tonight" and "Hard Luck Woman" in the set for that tour, yet the fake 'crowd' sounds pretty much the same.
I have the bootlegs (either DVD or CD) for all the shows that were supposed to have made up those two albums. Some of the actual live cuts are close enough that you can tell exactly which night each song came from, but there was still a lot of work done on those tracks. On Alive (IMHO) it made for a much better album. Alive II? Not so much...
Of all the bootlegs I have or have heard (which would be multiple shows from every tour back to their first club dates), the one thing I've found is that there were times when KISS was a TIGHT band. When they were on they were as good or better than anything on Alive. The problem is, they could also be as bad in the other direction, and not just because of Ace or Peter's substance abuse. Gene and Paul ruined just as many songs along the way with their sloppy playing and forgotten lyrics (OK, that was usually Gene). Doesn't matter. You either like or 'get' KISS, or you don't. No big deal, but if you're in either camp there's no reason trying to convince the other side of anything. It's a losing proposition.