IMHO any person in the UK that has not got a direct flight to America should seriously consider using Dublin or Shannon because one will clear American Immigration and Customs much quicker and little or no hassle.
Of course it depends on getting a suitable connection from the UK through Dublin or Shannon.
The Aer Lingus Business Class seats whilst not fully horizontal are nearly so.
Tip - press the 'snooze' button more than once to get maximum horizontal.