Once it's up and running, it's not too bad. There's a bit of a bug in the release of Archbang I was using which broke the GUI when updated, but it's easy to fix, just read the wiki on the Archbang webpage. I feel happier using that than *buntu which tends to do quite a bit of spoonfeeding.
The 'shock' might be that Openbox doesn't have a start menu, per se, but it can be reached by right clicking on the desktop... and if that's really horrifying, you can install something like Docky and have an OSX-like dock on the screen.
Debian isn't Arch, by the way. Or vice versa, whatever.
I'm not a fan on the *buntu based distros; Ubuntu is based on Debian, so having a distro based on a distro based on a distro seems like having a middleman pointlessly.
The biggest 'negative' of Arch (which is also a positive to many) is that it's a rolling release, which while it means you're bang up to date all the time, can mean that updates break stuff occasionally. I've never had it happen to me, personally, yet - on raw build-system-from-scratch Arch, but I have with Archbang. But it won't update on it's own.
If that scares you, then the Debian based Crunchbang would probably be a better bet. Or just stick with Xubuntu; I just feel like *buntu's getting overly bloated.