I'm another Brit in the US.
I live in Michigan, close to Ann Arbor which is incredibly left-wing liberal middle class & educated (it's THE most educated city in the country).
I'd agree with all the pros and cons listed so far.
One other thing - it can be incredibly isolating to be the trailing spouse. DH and I are both British, but he had work to keep him busy, and I was horribly lonely and unhappy to start with.
I never get to have those conversations with people where you can say "do you remember the eclipse advert from Jaffa Cakes?" or people who know what I mean when I talk about the guides Christmas party back in 1983 etc.
But then, the same is true for your DH if you stay in the UK.
If he has friends/family there, do you have any idea how well you'd fit in with them? It would be awful if you felt like the outside while DH was happily reconnecting with all his old beer buddies. Or it could be great if you get on really well with them all and have a ready made group of people you know.
Is there any way that you could go for an extended stay, like a month, and look into it seriously? You could look at houses, schools, cost of living, spend time with people etc.
I think that marriages from different nations must be incredibly hard. There's always the risk of one of you feeling lonely and cut off, no matter how great your relationship is.