I'm not sure quite where I was when it got updated - I only checked the site after my client wouldn't login - only to find that my data had been wiped, and a brand new account system in its place. Thanks Mozilla. Meh, I guess they did warn me anyway when I installed the add-on.
A lot seems to have changed since the initial release, and a lot of the work seems to have been done on the GUI. It's now easier to use, and creating an account is easy. One thing I immediately noticed about the new version though is that it pops a small window up when you close Firefox and starts to sync your data. That annoys the hell out of me - especially if I want to shut down or something. I usually just hit the "X", but then Weave starts spitting errors at me when I next start it, and takes a while to settle back down.
Apart from that nothing much has changed on the outside - I bet there is a lot going on on the inside. It looks like a really promising piece of software though, with the premature "addons" tab that happily informs me that addons and such will go here it looks like Weave will be a must have addon when the project really lifts off.