Makes sense... I think if you're a control freak, that's when it's really important to have someone who shares a brain with you and writes up to your standards. It's hard when that isn't the case.
For me, though, reliability is the biggest thing. I've written with some lovely co-writers, but I always end up getting bailed on in the end because my enthusiasm for the project usually lasts longer than my co-writers'. I can't handle flaky people; I like to finish what I start.