I grew up in Oregon but have lived in the UK for the last 4 1/2 years (with NO intention of returning to the US), thus have experienced plenty on both sides.
US experience:
As a kid we rarely went to the doctor unless it was *really * bad. The cost was just too much for my folks. As a teen (16) it was worse, especially when I crashed my car into a tree ending up in the ER, the ambulance bills, etc. I had to get a job to pay the bills as my folks couldn’t afford it.
Watched as my folks were forced out of their insurance when dad found out he had cancer. Their insurance went from a couple hundred dollars a month, for the two of them, to nearly a thousand. How the hell could they afford that?? It was quite sad.
The last time I was home (to say good bye to my dad as he died of cancer), I found out I was pregnant. One night we were in the ER with my dad when I started cramping badly. Nurse asked what was wrong and I told her (impending miscarriage). They rushed me back to be examined, scanned (found twins), bloods taken, etc. I told them OVER and OVER and OVER I couldn’t pay AT ALL but was told it was hospital policy to take anyone and everyone regardless - they just took my UK details and got on with things. Two weeks later my dad died. Two weeks later our other twin died. Few weeks later *hubby * gets a bill from the hospital in the US demanding payment in full of over $2500!! We were SO pissed off it wasn’t funny.
UK experience:
On my second trip to the UK I got off a train, raced up the stairs to get to the pub and rammed my shoulder into a phone box sticking out of the wall. Friend to me to A&E, but I was worried about getting a bill for thousands of pounds. I explained my tourist status but was told not to worry about it. X-rays, doctors and such were all free! Nothing broken - what a relief - but had badly bruised the bone and couldn’t move my arm for a few days.
In the 4 1/2 years of living here I’ve been diagnosed with diabetes, had carpal tunnel surgery, my gall bladder out (subsequent emergency surgery from major infection), and a C-section that had me in the hospital 4 days. All free.
Was able to sign up to a GP as soon as I needed to see one - GREAT fella by the way. When we (hubby or I) need to be seen it’s usually within a day or two. We’ve also had several home visits when I’ve been too poorly to even get out of bed, let alone the house. No extra charge here - unless you count the cuppa tea he gets 
I’ve paid private a couple times for dental treatment and laughed at the cost. Paid £30 for a mouth guard as grinding my teeth was loosening several every night and it was getting bad. Also had a bad tooth ache and saw private - think I paid about £15 (?). People complain about the high price of private dental but in comparison to US prices it’s cheap as chips!
Prescriptions and dental treatment are free for elderly, children under 16 (18 if going to college) and those with medical conditions requiring lots of meds. Pregnant women are also exempt from paying for prescriptions and dental treatment.
Which do I prefer? Despite having every gadget under the sun at hand in the US, I prefer the UK treatment I receive.
The NHS isn’t perfect by any means, but it beats having to bankrupt onself to get medical treatment.