I've been treated for serious conditions in the following:
US Military hospital (Madigan, WA state)
US "University of Washington" medical center
UK Edinburgh Royal Infirmary (prior to the move to a new facility)
I feel that my treatment was equal in all three locations. However, there were great differences between them (all three places were treating the same life threatening blood disease that I have).
I felt that the NHS was over-treating me in many cases, and it was difficult to convince my hemotologist to see me one a month, instead of once a week. They wanted to medicate me straight away, and were very keen to keep me in hospital overnight for transfusions.
The military hospital wanted to keep me at hospital for a few days, but once I was gone, they only wanted to see me 3-4 times a year. Medication was at a minimum (though still more than I wanted, because of side effects).
The UW in Seattle was great. My hemotologist saw me monthly or quarterly, based on the severity of my condition at the last appointment. They were not happy about my wanting less medication, but with a promise of "being careful" and not falling down any stairs (bleeding disorder and all) they agreed to the bare minimum of drugs.
Overall, I feel confident in the care I recieved from all three. The NHS, in my opinion, treated me too much, as I really didn't want to be "sick" going to see doctors all the time. But, as the condition can be deadly, I can understand, and apprciate, thier overzealous manner.
Now, when I was just going to see my GPs in both countries, I can not see a real difference. Both places make me feel rushed, and I feel as if I am not being given the time and consideration patients should have at an exam. I feel that is an improvement which both nations need to work on.
I would not hessitate to recieve care from either country.