Unless you care about the 3D aspect I think the SGS2 will be a better all-rounder.
I care zero about the 3D gimmick (although it is cool).
I want Evo3D because it's a beast of a phone offering 1.2Ghz dual-core. It will be the fastest phone out on the market for sometime, at least til end of 2011.
I'll be upgrading from my humble Blackberry Tour and am looking for an all-in-one portable multimedia machine.
Galaxy S II has 480 x 800 resolution = 384,000 pixels
3D Evo has 540 x 960 = 518,400 pixels.
That's a whopping 35.2% more pixel count than Galaxy. People say Galaxy has a nicer screen quality, but there's no away around the sheer resolution difference.
Evo3D's aspect ratio is perfect quarter-HD (qHD). So all youtube vids, movies and media will be displayed perfectly.