We're in the process of moving back, and don't regret it (yet). For us, the prices in the US are hard to beat when compared to London. In London, we can't buy a house for less than 300,000 pounds, and that's only a terraced house. In the US we can buy a place for much, much less. And, in London we spend 2-3 hours a day commuting, trying to run the kiddies around, and basically doing little else aside from work. In the US, my DH will have a 10 min commute and I get to stay home with the kiddies. I cannot wait!
Not sure what regions you are comparing for prices, as for me it's the opposite. Our local is 3 quid a pint, which is nearly $6. In the US, I never, ever paid that for a beer. Here we pay 8 quid for a burger and chips and any comparable place in the UK is less than the equivilant in $$. And, for me the clothes are much, much cheaper in the US...love Target and Old Navy for the childrens clothes! Most things except fresh groceries are lower (although packaged groceries are much lower so it balances out).
We did a trial run in the US for 3 months and decided to go for it.Yes, college and things are more expensive, but there are the new tax-defered savings plans for children that make it doable (anyone can contribute and take a tax savings). We have booked health insurance for us that is $170 a month for our family, and that is much, much less than DH and I paid in NI tax. And, the number of tax deductions available will lower our tax rate significantly--will be nice to put that into our savings.
A lot depends on your situation so it's hard to say. And, as we live in London in an awful NHS trust area we have different set of challenges that others might not face (commuting is long, no recycling, dirty streets etc). We're making sure that our new life in the US incorporates the things we like, such as walking to a town center, and we'll be glad to avoid the crime and grime (we've picked an area with non-smoking in place and excellent facilities).
I absolutely love the UK, and am very sad to leave, but I welcome the escape from the negatives we encounter, as they've become too much.
Good luck with your decision!