The worst offender I've seen is Rush, in every concert since the Presto tour, they've just been so loud that I couldn't hear any individual instruments. Coincidence?

I think it depends on the venue. When I saw them on the Counterparts tour, it was in a small indoor arena - it didn't sound too well. However, on the Vapor Trails tour, I saw them at an outdoor venue. I think it sounded a lot better, and I enjoyed the concert. Then again, maybe it was because I hadn't seen them in so long.