1. Isn't Southampton really good for Engineering? My uncle is a fellow or something and whenever I see him he goes on for ages about how good it is, but then again he would be biased.
3. Nice city, not too big not too small.
4. Reasonably cheap to live in
5. Lovely campus in general (maths building not so much!)
6. SU is pretty good, lots of stuff going on.
7.Good choice of accomodation, good mix of what's on offer and good price range.
8. Southampton very focused on Graduate Recruitment (compared to Cardiff certaintly, whenever I see my brother he raids the Soton Graduate Recruitment site as most unis have nothing nearly so good).
9. Sports are pretty good here.
10. Ditto societies, there's a society for pretty much everything, and if there isn't you can start your own soc very easily.
This all said without any idea of what Sheffield offers btw, didn't look at the uni there.