Surfer, Strange, and BM are on the same level, with Strange being the most variable, upside and downside. Hulk is also essentially on the same level, but it's the Hulk...who knows how powerful he will be on any given day.
So team 1 has 3 elite top tiers, and Team 2 really only has 1. However, Marvel, Spectrum, and Chavez have gotten a lot of props and can make an elite top tier work. Team 1 also often has had horrifically bad teamwork, whereas the Ultimates are pretty good at teamwork. Still, it's not enough to overcome the power gap.
I don't think it's quite as clear as some of the other posters seem to think. BM and Spectrum can both power Carol up to Binary level. BM can and has knocked out at least one version of the Hulk and has also taken Namor out. Spectrum and Chavez can both blitz the Hulk and Namor. Hell, Chavez can drop members of the Defenders into different realities. I also don't see the hulk doing any damage to the Ultimates.....like, at all. Fighting intelligently, none of them are going to even let him touch them. The only members of the Defenders that are real problems are Strange and Surfer IMO, and I'm not sure if they're big enough threats to take down this team.