Can you expand on the "jaw-dropping nastiness you have to go through to make it work"? Seems pretty straightforward, though I have not tried to actually use it yet.

https://docs.djangoproject.com/en/1.5/topics/auth/customizin...

It appears the database migration is the biggest hurdle, but I don't think there's a way around that. User profiles require a join and that can be suboptimal, which is why this is a useful addition. If you weren't running into problems before it's probably better to not change (though that's usually the case for working code).