I think it depends on the venue.

Untrue.

I've been to many concerts at the same venue (Arco Arena in Sacramento) by many different bands. Some sounded utterly fantastic (Peter Gabriel and Yes), others sounded like crap.

And I have heard many Rush concerts at the same venue, but on different tours in different years. Sometimes they sound great, other times they sound like crap.

In fact, I saw one concert there (Jethro Tull) where it was fine for most of the show, but the sound levels got progressively louder as the show went on, and for the last few songs it was nearly unlistenable.

So it's not the hall, it's the people manning the sound equipment. I will agree, though, that outdoor concerts tend to fare better than indoor ones (although I've heard my share of crappy-sounding outdoor shows, too). Outdoors, the people running the sound board don't have to deal with the internal resonance of the hall itself. It's much easier to mix an outdoor show.

That's one reason I'm looking forward to the Vapor Trails concert next week, it will be outdoors.