The first U2 concert I saw was Zoo TV, front-row, Boston 2. It was the moment that took U2 from being a great band (a status cemented by R&H, JT, and AB -- the three albums I owned at the time) to The Best Band Ever. That show was fantastic -- So Cruel live, Sunday Bloody Sunday instead of Bad, etc. For me it is still the high-water mark any concert will be judged against.
People who slag the lack of variety within the setlist need to remember that U2 was reinventing itself at this point in time -- taking a conscious stand away from their anthemic past. As a result most of their songs had to be put in deep storage, which meant that they didn't have a large pool to draw from. What was Bono's quote? "To me, Achtung Baby is the sound of four men chopping down The Joshua Tree." There wasn't much for them to fall back on -- they weren't going to do what they'd done before. Add to that a show highly structured after a Broadway show, with characters and movements, add technology that they were learning as they went along (BP Fallon's book Faraway So Close talks about how five weeks before the show they were still learning the technology -- and two nights before the first show they threw out the Dead Cowboy/Bono winched up in a harness thing they wanted to do at the end of Running), and you have an idea of how restrictive that tour was.
And to those who say that Lovetown wasn't the hardest tour they've ever done, I refer you to both U2 Show (which documents Bono's vocal problems and the tensions they faced), and U2 at the End of the World, where Flanagan says that U2 had become fed up with being the world's greatest jukebox, their anthems reduced to sing alongs. "At one point they were so bored they came out and played the whole setlist backwards, and it didn't make a difference."
Sorry for the long post. As usual, interesting stuff, all....