|i like the fact that the UMU is much tighter and more cohesive than the mainstream MU or the DCU, and that it has a single overarching Big Issue that grounds it all thematically, the way that the mutant/human issue grounds the X-books in the regular MU. Nick Fury basically sums up the UMU in a nutshell while talking to Cap in Ultimate Six. i don't have the exact quote with me, but essentially he says that there were two big technological success stories to come out of WW II, the bomb and him (Cap), and since then everyone with a petri dish has been trying to make another super-soldier.|
you can see why they'd want to in the very first arc of Ultimate X-Men. as much as the series may have a lot of weaknesses, the basic approach to this is absolutely perfect: Days of Future Past, except without the future part. a lot of people think that this whole approach is too extreme, but if we had teenagers walking around right now who could shoot lasers from their eyes, control minds, and walk through walls, and the government had Sentinel-level technology, i guaran-fucking-tee you this is what the world would look like. and, frankly, understandably so, considering the utter havoc Magneto is able to wreak on the world in this arc.
Magneto's rampage through DC sets the tone for the Ultimate universe, and basically the world looks like this: mutliple avenues to almost godlike power are opening up in every direction, from alien technology to mutant powers to extradimensional/magical/divine(?) abilities, and the powers that be are doing everything they can to control, suppress, harness, or counter those powers as they emerge, and in the mad scramble for supremacy, real people's lives are being blown around like leaves in the wind.
Spider-Man is an accidental byproduct of a failed attempt to recreate the super-soldier serum, and look what it's done to his life. look what the Weapon X program did to Wolverine, or what the Baxter Building project has done to the FF and Doom, or what the displacement through decades did to Steve Rogers' life. etc etc etc. all this in an atmosphere of chaos and paranoia and massive destruction which reflects our fears about WMD proliferation, genetic experimentation, terrorism, shadowy government misconduct, etc.
the Ultimate universe really feels like the world i live in, and those characters who have actually been developed (a lot of them haven't, which is a big flaw) seem to lead real-seeming lives, all of which tie together to create a mutually reinforcing world-system.
obviously, some of the books fail to deliver on the potential there, but the universe itself is really well-done.