im from Bristol, and as mentioned there is alot more grenery and picturesque sites in Bristol than you might think. I cant comment on Notts as i havent been, but id certainly say from what i have seen of reading (mainly train station to festival) there isnt much difference. Some parts of Bristol are absolute dumps, but that is to be expected of bigger cities. Remember also Bristol has the docks running right into the centre of Bristol. Bristol is also only a 20 min drive from Bath, with lots of picturesque sites and very close to countryside. Bristol has great access to other cities in comparison, and a bus can take you almost anywhere although they are a little unreliable. Bristol also has 2 unis (Bristol and UWE, so the student population is huge, and the chavs here are really quite friendly) so you shouldnt find it hard to make friends.
People always go on about bristols night life, but i personally dont feel its that great, maybe its just because i live here and under-appreciate it.