The Beatles and U2 are very similar and very different. Similar in the way that with casual listeners, like you and me (I only have one Beatles album myself) some of their work does sound the same. The causal U2 listener could argue that "New Years Day" sounds a lot like "Pride", or that "Elevation" is the same as "Vertigo". But like U2 the Beatles have gone through periods of changes, and different sounds with certain albums, even though they're career was seriously shorter that U2 (only seven eight years I believe). For example, "Lucy in the Sky With Diamonds" sounds nothing like "Helter Skelter", much like "The Fly" sounds nothing like "Beautiful Day". The one thing too that has to be remembered is that with a band like U2, alot of their songs and "trademark sound" is built around tons of electronic effects. We've all seen the giant board at Edge's feet with the crazy labels that he uses at shows to get different effects out of his guitar that can abruptly change the atmosphere.