I used Missing Sync for about a year now and once I got the initial bugs and confusing instructions ironed out, it worked great. I recently upgraded based on the claims that it supported multiple calendars better and was more stable all around. I spent way too much time getting everything to jive again. I guess it tries to involve iSync somehow and it basically ruined everything. Having experience with this sort of process, I backed up everything beforehand. I finally got it going acceptably but with slow syncs, all kinds of messages pertaining to iSync and extra calendars in iCal everytime. I finally figured out how to turn off the iSync sync. If you don't need any of the new aspects in the new version don't upgrade. There was nothing there for me; I don't have an intel proecessor and I don't use iSync or .Mac. Also, my digitizer gets out of alignment after each sync. I may try to revert back to the previous version, but I don't know if I still have a copy. The Missing Sync can be enraging to install and tweak to perfection, but once it's going, it does everything pretty well and it's the only thing I know of that does it at all.