I live in Bath, so quite a bit smaller than Bristol, but I really apprecaite the fact that we can be in the city centre in half an hour, or in the countryside in 15 minutes.
If I didn't live in Bath I'd probably live in Bristol, it's a great city. And I absolutely agree that it's kind of the perfect size for a metropolitan area.
I think a lot of London is saved by having so many parks, and so many large parks and commons. I know Paris has a lot less green space than London and when I visited I definitely felt that.