Flew LHR to Houston last year with BA (B747) with a total pax count of 4!
Realistically economy is economy, a few little variations but seriously for a few hours of your life it isn't a real hassle. I fly 60 - 70 long haul economy sectors per year with various airlines, eventually you become immune!
Business class varies massively from airline to airline, often without a noticable difference in price. Expect lie flat beds, cubicals, champagne and great service with one, then a little bit bigger seat and no alcohol with another (well at least most of the smaller middle eastern airlines!)