Interesting discussion here. I checked into the UK page and stumbled on this. I have lived in the UK too, and I specialize in compensation & rewards. I am not from the US or the UK originally, but I would pick the US over the UK any day of the week.
Now as to the original question, it all depends on the terms and conditions of your job. If they localize your job in the UK than means you will be offered local market pay. And when it comes to local market pay, compensation in the US beats compensation in UK every time. There is just no comparison. A software engineer can make 150K USD here and for the same job he will make 80K GBP there. Purchasing power is much higher in the US. If you receive medical/vacation benefits, which everyone who works for corporations receives then you are better off in the US.
The UK only beats the US in cost of living when you are a really low earner, and by the sound of it you seem to be upper middle class.
I would only consider living in the UK (again) if I was offered an EXPAT assignment. This means the company would have to guarantee equal COL and purchasing power between the two countries. This usually means you get extra allowances, stipend for housing, etc etc.
And let me say this, even if I made the same money in the US and UK, I would still pick the US because I love my guns and my 2A. Over there you won't be able to own anything. But if you care about travel and such, then OK, it's your call. Just remember the key difference is expat vs. localized employment. Try to get the expat deal (much more expensive for the employer)