@Newdeath: John never reconstructed an entire solar system. They were just empty constructs devoid of life. Many guys can make empty shells with no complex eco system and even as just shells, the ring couldn't do it. Yes, Buu can survive and reconstruct himself from a single cell much like cell. Shown several time when Buu evil Buu was released and when fat buu was blown to smithereens. I think your also overplaying anti-monitor defense stat too much, he's not that durable compared to some others and has become the biggest jobber since Geoff wrote Sinestro Corps war. AKA PIS
@Greysmokeman: Buu is not a galaxy buster. He's a solar system or even multi solar system buster at best (as are most of the Z fighters at the end of Z with the exception of Vegitto). A galaxy is several hundreds of solar systems or more.