I've personally observed one excellent experience with the NHS and one absolutely terrible experience. Both emergent situations - the good experience was a broken leg with very obvious deformation. Treatment was quick and they did absolutely the right thing. However, we saw patients with similar problems who were not treated right away, some waited a week for their surgery after a broken elbow resulting in a totally deformed arm!!!
The bad was a possible stroke and they did not do ANY of the definitive diagnostic tests - they just dismissed it out of hand because of age (even though the GP was convinced it was a stroke and gave the appropriate referral!). I KNOW that in North America (even Canada with their socialised health care and the US with the insurance we had), they would have done the necessary tests to rule out or diagnose stroke. Here, for whatever reason, most likely post code lottery and they'd used up their quota for the month, they would not do any of the necessary tests. Then they gave a diagnosis and after doing a bit of our own research, we learned that they didn't even do the appropriate tests to rule that diagnosis out OR in! Also, the emergency room doc we saw initially, told us to "go home and look [the diagnosis] up on the internet"!! Which we did and saw that he was totally wrong!
The hospital where we went for both situations was absolutely disgustingly dirty. There is no way that any hospital should be in that kind of state. Even the toilets were so gross, I refused to use them.
I have to say, for preventative medicine, I have absolutely no faith whatsoever in the NHS. It is so difficult to get an appointment at our GP that most times, when we would go to the doctor otherwise, we just don't bother.
And also, when we went for immunisations at our GP, the nurse did not sterilise the area before injection. She used no alcohol swab at all. I thought that was absolutely standard procedure.