It's hard to become as massive as U2 without picking up a ton of detractors. People have been labeling them "sellouts" ever since they first landed on MTV with "Gloria." Some fans of their early 1980s college rock-period didn't like arena anthems like "Pride (In the Name of Love)," while the futuristic sound of Achtung Baby lost them some fans they picked up when "With or Without You" topped the charts. When you change as much as they do, it's impossible to hold onto everybody: even fans who stuck around through Pop found some of their 2000s work a little safe and underwhelming. The 2009 record No Line on the Horizon really deserves a second look but, still, when you factor in the relatively dud sales and the Spider-Man: Turn Off The Dark debacle, it's not surprising that some people have had enough.
U2 are extremely aware they have something to prove this time out, and they've spent years and years prepping their new album with producer Danger Mouse. It'll be fascinating to see what they come up with. If history is any guide, they do their best work when their backs are against the wall.