I've been using Xubuntu 7.10 recently too. It really has come a long way. I still think Ubuntu is sluggish though. Xubuntu is quite a bit more responsive, but really not so well supported as the big brother.
For people comparing Linux distros, in my opinion, it's a matter of opinion. I think one main factor is what is going to work for the user, and provide a sufficient user experience, with a suitable level of committment to technical learning. These things really vary between users, and distros.
Great thing about Ubuntu, is it really does provide a high degree of good automation, but it also doesn't really limit the capacity for experimentation and customisation to users who want to look inside the box. It also has a good amount of accessible documentation, and a big user base for support. Commercial support is available too, which really is handy for the corporate customers. A lot of stuff really does work with limited hassle, depending on the user environment.
It still can't come close to being an XP replacement for me. Too many of my development tools are XP only (Vista also can't offer replacement for these). Also, hardware support is still lagging somewhat, as many vendors just can't be bothered with it, for much lower returns than Windows can provide. This is particularly an issue if you are migrating your hardware from Windows to Linux, as a lot of gear isn't supported in a hassle free manner.
Hardware support in 7.10 is a lot better than before though, and a lot of people won't ever need to learn the joys of ndiswrapper.
The native office suites are good for making one's own docs, but still can't handle MS Office's unique approach to formatting, in many cases.
I've always liked the range of free code development tools on Linux. Used these enough in uni to see their appeal. Provides good access to parallel processing, and lots of handy simulators to analyse runtime performance in a range of applications. Very powerful, for people interesting in using a computer for computing.
I think Linux can only ever be a secondary OS for me though. Like most people, I'm locked in to the Windows based tools. I don't quite trust Linux to provide sufficient Windows emulation when doing firmware development for my employer. XP is still very useful, and there are plenty of ligit second hand licenses available now.
OK, a bit more than my 2c here...