I went round Wills when I went down to Bristol
It is very impressive! I was actually completely amazed by the fact that Wills is also nowhere near 40 minutes from the university buildings! Basically, there are two quads; rooms are very good.
It is possible to organise to go and look round Wills, and the very friendly woman I spoke to said that if you want Wills as your first choice you need to show some evidence of having specifically chosen Wills as the best hall for YOU.
The students I spoke to were generally quite public school, though not in an overtly bad way. It was not, however, completely public school.
My concern with going to Wills would be seeming like a pauper when I'm doing my part-time job etc. Another flaw of Wills is that you get no guaranteed vacation residence, and even if you get it- it is quite expensive. This is worse considering the fact that the rent for 30-week is not really much better than the 38-week lets for some other halls.
Overall, Wills is a great choice. I don't think I'll apply- I'm probably going to go down to Bristol again and look at all the halls and then make my decision. The heavy degree of public school students in the hall is, IMO, a result of the obsession with communal dining and formal dinners and the focus on hall sports etc.
I would definitely look round, preferably during term time, and really try to get a feel for the place.