I want Canonical and Ubuntu to kick butt. Mark seems like he's really making an effort to be a "product" person, which open source could use more of. Bravo! (And this has always been reflected in Ubuntu, which I really appreciate.)
Some nits: The new font is a step backward. The softness of the old font was both distinct, unique, AND comfortable. The new one is not as unique. And I don't think will age so well. (Plus, fonts and logos are not something that need an overhaul as often as themes and campaigns. I just think it was maybe too soon to overhaul the font. It was a strong brand.)
I LOVE the new colors. Yeah, there's an Apple overlap, but I don't think "APPLE!" as soon as I see it.
Window controls on the left: I don't like it. I have desktops on all three major OS's, so it's not because I'm trained for one way or the other. There's just something that feels better about them being on the right.
Overall: I'm giving it all a chance, and will jump in with both feet when it's released, without undoing the major changes. The main point here is: They really care and have a vision. Whenever somebody makes a tool/OS/webapp/meal with a really specific vision, i always give it the benefit of the doubt, and try it THEIR way, not bending to my preferences or instinct to add salt/take off the tomato/go to my favorite theme/etc. When I don't try stuff with that trust, i often miss out. I hope Linux users give it a fair shot, even if stuff feels funny at first.