First off, Guns and Roses at their peak had notoriously bad live shows, usually cause axl just wouldn't show up or they were too fucked up, now guns n roses is axl and session people, so yeah, it makes sense that a cover band led by the original lineups biggest liability in a live setting they'd suck. Acdc kept a lineup for the most part aside from the bon Scott thing. I've seen people their age and older either rock way harder in the case of some older punks in reunited or new bands or just have a more well put together and rehearsed set. This also would have been in 2008 or so.