Healthcare probably isn't that bad. If you've earning enough to afford healthcare (which I assume you would need to be to get a job which allowed you to get a working visa)
This. I you move there then you will be a skilled worker, and by definition will be getting good health cover.
From my personal perspective I would take the US health care over the UK any day, it is light years ahead of the UK, makes the NHS look like some kind of 3rd world field treatment center.
From an altruistic perspective it is far from ideal, although people tend to paint a worse picture of it than it generally is. You wont get left on the side of the rod to die without insurance, hospitals have to trick the sick. With the obamacare things took a big step forwards.
Workers rights are also liekly not an issue. If you are a professional working for a big company then you have similar rights to what you would get in the UK.
If you want to live and work in the US for a few years, or a few decades even, these things are really of no concern. They do become an issue if you want to permanently live here and become US citizens, then you have to think long and hard about such things from a moral perspective, e.g. will your grandchildren be happy with the situation?
Personally, I love the US. Paid way more, far more job opportunities in high tech, lower taxes, lower living costs, and there is definitely more freedom here. When I lived in Oregon what I loved was all the forest roads (dirt tracks but oc major ones pave) were completely open for the public drive along, because it is public land. Complete contrast to the UK where the Forestry Commission that own public land block access to the public. The flip-side of increased freedom is people are free to own a gun.
At some point we plan to move back to Europe when there is a good job opportunity. Definitely wont be the UK though. We miss a few European things, going to a street cafe, nipping over to Italy for a log weekend, politics hat are only moderate right not far right, historic cities, diverse cuisine, etc.
But I wouldn't rule out that we stay forever. My wife gets around $150K PA, the same jobs but with a higher workload in the UK would barely pay $50K, somewhat similar for my job, we then pay less taxes on his , have a higher standard of living and our house costs 1/3rd of what it would in England.
If we stay in the US long term then we will end up with a ski chalet in the mountians, a big yacht, a holiday flat in Florida and be able to live a real luxury life.