I've just done the sums for a RAF Sqn Ldr OF-3 and a USAF Major O-4
For a level 5 Sqn Ldr on enhanced Flying Pay then it is £67,737 per year, but for a 22year+ O-4 Major on flying duties with married/accompanied BAH for Nellis then it is ~£73,770 (assuming $1.6 to the £1). So yes, USAF servicemen are better off and they get a 1.6% pay rise this year (2012).
The only thing is that I usually have my fill of living in the US after about 2 weeks and want to eat some decent food, walk on pavements to the shops and drink some decent beer!
But is that worth £6k a year!!!