By upper-class do you mean like the aristocracy or like, say, a BBC presenter (otherwise known as RP)?
I am English and I am more towards the BBC end of that scale even though I was raised in the North East. I find the way the aristos speak rather affected and annoying. Stephen Fry on the other hand is one of my favourite people. Also, some of the things he says might not be so funny if he didn't talk that way.
As regards to how other people see me? The accent is generally a boon in certain circumstances i.e. jobs, as it is often seen as a sign of a good education, but there have been many people who have taken offence at the way that I speak getting really chippy and saying that I feel that I am superior to them. If they only knew! It was especially problematic when growing up in the North East, kids can be especially cruel when you don't fit in.
As far as attraction is concerned a lot of women have said that they like the way that I speak but, for my part, I can't say that I have a preference except in two cases, firstly, I have always been overly fond of women with soft geordie accents for some reason and secondly, I cannot actually bear to listen to a Liverpudlian accent at all without wanting to punch the owner of it or run screaming from the room.
I can do a quite passable East London accent too. Being a 'social chameleon' has been helpful in the past but I no longer do this for some reason. Either I have become more comfortable with who I am or I just don't care anymore.