I noticed no difference in the scarring, I have had sutures and staples. Got quite a nice, thin scar however I would recommend the sutures rather than staples, they seem to heal better and hurt a hell of a lot less when they get taken out! Staples are sore haha.
I had sutures last time and are having them again. I didn't have any issues and my scar is just a tiny little 'pencil' line. I had staples when I had back surgery and it put me off them for life. It took a long time for the wound to heal and it really hurt having them out but they could have just been a one-off bad experience.
I've only had staples (had 2 so far, going for my 3rd in 3 weeks), & I had some issues with them last time. One of my OB's partners sent me home with them & she told me I should have had them taken out prior to discharge. I was in quite a bit of pain until I could get in to see her. I've heard sutures are better because they dissolve. If you have a choice, I'd recommend the sutures, however I can't speak to the scarring issue.
Good luck with your delivery & congrats on your baby!!!