To answer such questions I always imagine transplanting a random citizen of country 1 to country 2 and vice versa. In other words, I guess you should ask the expats.

Having lived in both the UK and the US, I would say that anyone not rich is still much better off in the former because of the free healthcare, better infrastructure, cheaper education, etc.

However, in my experience the UK living standards (again, for a non-rich person) are significantly worse than the rest of Northwestern Europe. And the UK's trajectory is not looking good.