Is Oxford a nice city?

I am going to Uni there in September, is it nice, is it fun, is there a good social scene, is it a safe city? Are the shops good? Is there anyhting interesting and unique there, as in touristy? I live in Ireland, and am going there on an exchange thingy for a while, I'm originally from England, I'm English, I know South East London very well, that's where I'm from. I also would know Manchester some what but not as good as London. What would be the cheapest way to get down to South East London from Oxford like for the weekend? What kind of people will be there in Oxford, will it be mostly English, will there be many Americans, Europeans, Asian, Australians etc? Do you think I'll like it, is it a friendly city, or is it quite reserved, I would like to make lots of new friends! Is the nightlife good, what about gay bars, do they have any there? What is the gay scene like in Oxford are the boys/men good looking, I'm bisexual you see! :)