Hey I'm a first year at Southampton studying EE, I'd be happy to answer any specific questions you have.
I'll try to keep this brief because I've done quite a few long posts about So'ton's ECS department and it's getting a little exhausting haha.
Department gets lots of money, as it's probably both the best and most renowned department at Southampton. Teaching is both good and bad, but that's to be expected I suppose. Course is really interesting, labs are very tough to prepare for and carry out to a high standard but they really help our learning process! Work is literally non stop; all labs (roughly twice a week) are weighted for one module or another, we have coursework assignments more or less once a week, and a few class tests here and there. We had two design projects in January which were killers, but just get smashed on the night it's finished and you'll pick yourself up again haha.
The city has great nightlife, but Manchester's is probably better, since it's rumoured to be the best in the country! Having said that, Southampton's IS really good, you'll have a great time partying wherever you go. The campus is great and the bus service is really useful albeit slightly unreliable at times (free bus pass for freshers though!).
The difference in offer is probably something to consider. Last year my Manchester offer was AAA and my Southampton offer was A*AA so that was a reason why I chose Southampton since there's no point having an A*AA insurance, may as well aim high if you get the offer!
Hope this helps.