Not the expression of uncertainty, but rather the Emergency Room of Pacific California Medical Center, where I spent 7 hours today after my back went from bad to unbearably agonizing. So now would be a good time to compare my own first-hand experiences of the two systems.
Registration: I search the NHS website for a bunch of nearby doctors. In Finsbury Park I am told there are none nearby accepting new patients, so I never register. In Stockwell they are accepting new patients, so I come in, get a routine medical exam, and fill in a lot of forms.
Treatment: I call at 9 in the morning and can have an appointment at 3.15pm. I arrive at 3.15, wait briefly in a quiet and empty waiting room, and am seen by 3.30. My doctor prescribes me some basic medication and sends me on my way.
Payment: treatment is free. My prescription costs a flat 6 poounds.
Registration: ongoing. I choose a healthcare plan out of 5 offered by my employer, and choose a doctor from their list online of GPs offering new patient registrations in my zip code. Apparently this database is not 100% accurate, as it turns out the GP I wanted isn't accepting new patients until April, although eventually I am given a list of doctors who are accepting new patients today, some quite nearby.
Treatment: I am unable to find a doctor who will treat me at 12pm on a Friday -- the best I can find is an appointment by Tuesday. Not good enough: next option is ER. Arriving at the ER by cab, the waiting room is small, and contains a foul-smelling ancient drunk who mutters constantly to himself and anybody nearby in the phlegm-laden voice of a lifelong smoker. I wait half an hour and am seen by a nurse, who triages me, and I wait 2 hours after that as more urgently ill patients come by -- acute pain being, after all, by no means life-threatening.
Eventually I am admitted, and a nurse and a doctor examine me one after the other, determining it to be, as I suspected, merely an acute muscle spasm caused by back strain from lifting heavy objects earlier that week. Apparently the third day after such an injury is typically the worst. My back is quite trashed by this point though, so I spend the next 4 hours on a series of IV treatments of muscle relaxants, painkillers and anti-nausea drugs (to counteract the side-effects of the first two) until my back has subsided from unbearable back to the mere painful it was the day before. I am very grateful, even if the drugs do make me keep passing out, so they keep me around a little longer until my blood pressure returns to normal.
Payment: free at point of treatment -- nobody asks if I can pay prior to treating me. I am in an unusual situation of having healthcare coverage but no proof of such, as my registration cards have yet to arrive. No matter, they will bill my insurance later if I just provide the numbers, and if I can't do so, they will bill me and I will have to claim reimbursement from my insurers later.
In summary: it's not really a fair comparison. I've never been to an ER in the UK, and I've never had a regular appointment in the US yet -- and I've found it just as difficult to get registered with a primary physician (aka a GP) in both countries. So so far, a surprising tie.