Glad to see you have made a decision to move to the US.
I moved here in 1993 when I was 29yrs old. I came with a nursing agency, planned to stay 18 months...............and here I still am.
In terms of economics I am much better off here. I live in GA where the cost of living is relatively cheap. We are in the process of looking for a new house and can get a 4 bedroom ~2000sqft home for around $180,000. Something I could never afford in the UK on a nurses salary.
I bought a new car when I moved here, and am planning on getting a new minivan in a few months.
The climate is obviously much warmer than the UK (though probably about par with you right now with your heat wave!!)
Health care is good.....if you have the insurance (which even working for a hospital is expensive). I pay ~$250/month for health insurance, pay $15 for every doctor appointment, and $35 for a specialist. Most prescription are $10 for a month supply unless they are not covered by the insurance plan, then out of pocket expenses can be crippling. Many elderly people do not have coverage and unable to afford the medicines they need.
That said, I don't ever have to wait for medical treatment.
I don't have annual leave per se. My company gives me 8 hours of paid time off for every 80hours I work. Which only amounts to 17 days/yr, so I have to go without vacations in order to accrue a significant period of time off.
I don't get ANY extra pay for working holidays.
As I said, I have been here 10yrs now and have my US citizenship. I doubt I will return to the UK mainly because of the cost of living issues, although we miss family and friends of course.
Even living here however, we still have an idealistic view of places like Orlando (mostly I suppose because we have had just great vacations there), and have considered moving there. It is sometimes difficult to keep the memories of a good vacation separate from the logical reasoning of why we should or shouldn't relocate.
This certainly is the land of opportunity though and I would recommend to anyone to try it out if they have the chance.
Good luck with your decision.