I had both a vaginal birth and a c section prior to my jpouch surgery. Here's my take on both. I had to have a csection due to my oldest being too big for my body. (Couldn't fit through the vaginal canal) Baby measured normal and was 8 6 1/2 oz, Average is considered 7 1/2 pounds. So I was over a 1lb bigger and still measuring within reference. Second baby was induced in order to have a vaginal birth (I had already had my jpouch surgery scheduled and would have had to postpone it for a month or so with csection). Again, baby measuring average and 10 days early she came at 7 lbs 15 oz. So again, bigger than normal. The tears I had were extensive and while I deal with some leakage now I know if I wouldn't have had tears like that I would have more control.
I personally wouldn't risk being incontinent with a vaginal birth. I healed so quickly from the csection and truthfully it was not that bad. I was a mess down below for over a month with the vaginal birth and things have never been the same.
Yes you risk more adhesions but I'd rather deal with an adhesion than loss of control forever.