hmm, was nervous about the "beta" status, especially when ical was not called a beta and yet leaves something to be desired.
verdict on isync - it works. got d-link adapter today. upgraded to 10.2.1, installed backup for .mac (just in case), backed up, installed isync, paired T39m, synched 200-ish contacts and calendar. took less than an hour. went off without a hitch.
couldn't be happier - recommend going for it. can't imagine what will be improved in full release, but am ready for it.