Anil Dash was kind enough to see my cries for a Vox invite, and promptly sent me an invitation. I've currently only got a starter account, so I haven't been able to try out all the blogging features of the site, but at least the account puts me at the front of the line for when Six Apart starts handing out standard accounts.
If the rest of the platform is as easy to use as the profile management system is, I'm pretty sure I'll be switching to Vox for my personal blog. The ability to specify who I want to read certain posts is pretty tempting, as is the integration of all forms of media. It's like combining all the best aspects of WordPress, Movable Type, and TagWorld, and then putting them into one single package that is even easier to use than the sources they're drawing inspiration from.