I can give plenty more anecdotes: my aunt who has been crippled by a disastrously wrong leg cast, a friend severely hospitalized due to the nurse giving 5x the dose of a drug, my mum misdiagnosed with breast cancer (luckily she was all clear), the failure to diagnose my mum with gluten intolerance for 5 years, when I was 12 and sat in a seemingly empty hospital for 4 hours before I got my hand x-rayed.
I can also give many positive US anecdotes - never waiting more than a minute to see anyone, accurate appointment times, excellent service, and even very low prices even when paying fully out of pocket (I needed chest x-rays to get my greencard so had to pay myself, $150 is extremely cheap IMO). Of course there are plenty of counter examples, charging $40 a pill for aspirin is a complete joke (luckily covered by health insurance).
The US health system has huge problems and no one should go without health coverage. the NHS mostly succeeds but the service is far from adequate IMO. maybe my experience is extremely abnormal, but I have so many negative experiences with the NHS it seems more than a statistical anomaly. The latest screw-ups has persuaded a lot of my family to purchase BUPA cover so if they don't suffer the same fate as our close friends.
I want to like the NHS, free at source health care is very commendable, but the service in my experience is quite shocking.