it can't be worse than Dropbox...
Well, as long as Dropbox is around, I'll still use it. For the automatic sync. On every system, I install Dropbox, then set Sunbird to look in the Dropbox folder for MyCalendar.ics, and I never have to mess with it again. Change the calendar anywhere, and wherever I go, there it is.
And Dropbox is available for the Nook Color (which I'm planning on getting), too - now if someone will just port Sunbird to Android...