I prefer a side part. I am TALL and have long face and think middle parts make my face look even longer. So I always do a side part.
I looooooove a middle part on me. Side parts look incredibly awkward unless I place them just a little eency weency bit off center. Then again, it's pretty much a middle one.
I am also particular to the diagonal part.
So funny you started this thread because I just got my sew-in last night and I got a middle part. I have been wearing a side part for years and was extremely bored with it. I wanted a different look. I was afraid because I have a big head but my husband seems to REALLY like it. He keeps saying out of nowhere how much he likes my hair without me fishing or anything. I guess he was tired of the side part too.