I'm happy with Debian-Testing as my main desktop, but there are times where it can get tricky with the updates that are "held back". Never had a real issue tho.
On the other hand, Linux Mint has been a rock, it acts predictably, and it has mostly sane defaults. The fact that they're adding boot and services pref panels etc, clearly makes it even easier to use. Only thing missing now is a parental controls app to seal the deal for every household.