Yep, I see GigCalendar progressing at a good clip now on the forge and it's made me a bit torn about the prospect of parting ways with Events.
<melodrama> All the sweat, toil, tears and nervous breakdowns I invested in getting Events set up just how I needed it, only for it to be trumped by some new-fangled Joomla contraption with all the fields and relational tables I was haplessly trying to hack together all this time...</melodrama>
Migrating to GigCalendar for my primary site wouldn't be trivial, weeding out a few hundred events and 'venues' from Bookmarks to patch into new tables. And it looks like Events is getting legs to start up a new version, so I might stay put. But if you're starting a calendar from scratch, it looks like GigCalendar will be the obvious choice.
There are also folks on this and the Joomla board looking to jumpstart ExtCalendar as a fork from the first integration attempt made for Mambo. The lack of templates and 'non-nativetomamboness' initally turned me off, and both reasons are pretty invalid, I know.
But back to the Attend Events component, it looks like it holds the most promise. Instead of having a plugin simply spit out a user's events, the ability to manage invites or for peers to join roll calls or register for events posted by a user would be the kind of stuff CB was designed for.