You might have a different definition of "completely unusable" from mine, but have you ever compared XFCE and Unity on the same machine? I'm accustomed to a snappy DE. I don't expect to wait 30 seconds+ for the most basic desktop to show up on boot, and when I drag windows I expect them to move instantly with no visible lag. Unity didn't meet those expectations on my Mini 10v. XFCE does easily.
Yes. I'm running xfce right now, but I really don't see much of a difference apart from the lack of glitz. Memory seems to be a little bit lower, but not that much.
Another option for the memory constrained is Unity2D (and hiding the launcher for the pixel-constrained). It uses screen real estate a little bit more efficiently than xfce and looks nicer.
Weird, I might have to try it again sometime. I definitely remember thinking Unity's performance was horrible, but some of that may be confirmation bias (I expected going in that XFCE would be lighter than other options). And I was unaware the launcher could be hidden.
I'll second that. The first release with Unity (11.04?) was dradful. The second fixed some major issues, and now it's perfectly usable (unless you're particularly set in your ways). I run 12.04 on an older Eee, and it's not noticeably faster or slower than when I was running Xubuntu before.
