I've heard both the courses are good, some saying that Southampton's computer science course is better, but Durham is more prestigious - and is higher up in the ranking at 7th, compared to 15th for Southampton, if that matters at all!
I've applied to Durham by calling them up (clearing) while Southampton is my insurance choice. The only issue is because I've applied pretty late to Durham, and it has a collegiate system, I think the top colleges in Durham will be full which isn't ideal (I also don't know if I have to make a separate application for the college in Durham), and I will be given other colleges.
Most of my friends are going Southampton, and the course seems to be good, so I was leaning towards Southampton until now - but Durham also seems to be good (although I don't like the collegiate system and prefer the Urban nature of Soton).
Some advice would be much appreciated.