I don't use emacs. While I do understand the power of the terminal, I like a GUI just as much as the next guy.
I've never found the sync broken, and the only problem I have with mcalendar now is that it downloads ALL of my Google Calendars (which is annoying so I'm waiting on the update) >.<. But Erminig does the job quite nicely without any issues so far.
But what I'm saying is, for me I could never find it useful compared to my internet tablet for what I do with it. To do what I do on the internet tablet on an iPhone or iPod touch would require jailbreaking.