I absolutely had a blast in the open beta. The combat system is fast paced, fluid, and a lot of fun. The character customization, both in terms of what your character looks like as well as what they can actually do, is exceptional. The graphics are also lovely, at least if you turn off the thick black outlines in the graphics options.
My only real gripe is repetition in the starting area. Classes start out with two basic attacks that function nearly identically regardless of what class you pick, and you will be playing though the same tutorial with every new alt. But really in the grand scheme of things that's a pretty minor quibble. It takes maybe 15 minutes to gun through the tutorial area, and after that you get to pic from one of two main starter areas (one is a desert Hulk inspired area, another is a Canadian wilderness Alpha Flight inspired area). As soon as you get there you pick your first additional power and your first travel power (from many options), both of which potentially make a big difference in how your character plays. And from there on out is all gravy.
I'll definitely be pre-ordering this one, though I'll admit I'm a bit ticked that I missed the six month option. I also suspect that the naysayers that had their undergarments atwist right after the NDA went down either played early builds that weren't as polished as the current one, or simply aren't part of the potential audience for a game like this.