Yeah, when I first saw it, I thought it was butt-ugly. I still think it's ugly, but I do have to admit that I don't notice it that much during regular usage.
I just wish Office 2013 (decided to use the preview, hadn't used it before) wasn't so white. I always used the blue theme in 2010 because I thought the default gray one was too bland, and now it's even blander with no alternatives.
I have to wonder, if you were to show the Windows 7 and 8 desktop UIs side-by-side to someone who has never seen either (let's say, some hypothetical person who had never seen a version of Windows since Windows 95) and ask them which one is the more modern UI, what they would answer.
One minor annoyance so far: the "Computer Management" option in the right-click corner menu opens a non-elevated instance of MMC if you're a regular user (which I am), whereas the "Manage" option on the Computer entry in the start menu would always ask to elevate. There's no easy way to open an elevated computer management instance, since it doesn't appear in the start screen search either. Easiest way I've found is to open an elevated command prompt and run compmgmt.msc.
I'm also really missing the start menu MRU list and I hate that after every install I have to remove a whole slew of pointless tiles from the start screen. I'm also missing the Documents/Music/etc. options from the right-hand side of the start menu, and am slowly getting used to using a pinned instance of Explorer (I never had that pinned before). These are complaints I've made before.
It's not as bad as I feared, anyway. Metro doesn't get in the way too often, and the whole OS feels very fast and smooth. And since it seems the network issues that forced me to abandon the previews are gone, I hope I'll have a chance to see if I can get used to it this time.
It's weird, though. Ever since Windows 2000, I've been part of the process. I was invited into the technical beta for Windows 2000 at the beta 3 stage, and used it as my primary OS almost immediately (only falling back to 98 for some games due to driver issues). I filed bugs and conversed with the development team in the beta newsgroups, and when it was released I was proud to say I had some (small) part in the final product.
With XP I was there from the earliest days of the technical beta, before beta 1 even. I was very active during that one, installing every new build and giving a ton of feedback. And again, when it was released, I felt that in some small degree it was "my" OS.
With Vista, it started to get less. We got fewer builds, and it felt like the feedback of the external beta sites was less important than before. Still, some difference was made (like the return of list view in explorer), and it was still "my" OS, though less so.
Windows 7 was the beginning of the end for the technical beta program. There was less interaction with the devs in the newsgroups, and although they still listened to the feedback on Connect (since the old WindowsBetaWeb was no more), it felt we were somewhat out of the loop. This was strengthened by the fact that we got the same builds as the public (just the milestones), and that beta 1 was already so far along that there was no chance to influence the design like with XP or Vista.
I was in the Windows 7 SP1 beta. I might as well not have been. We were ignored. Only one build, never saw any MS people on the newsgroups.
Windows 8, I don't know if there was a real beta program like the old Windows versions had, but if there was, I wasn't invited (and I haven't heard about it). Sure, you could submit feedback on the public builds, but it felt like MS was plotting its own course regardless. And unfortunately I also didn't have the time to commit to an in-depth bug hunt like I'd done before.
So this is the first version of Windows where I've had no influence whatsoever over the final product. It seems that under Sinofsky the days of the technical beta program and being part of Windows are well and truly over. The end of an era, for me.