The service and food is supposed to be fantastic in First (never been in EK F yet).
However, the seating and entertainment largly depends on what aircraft you are flying on.
The A340-500 and new B777-300 have first class suites. These are probably the best you'll get in any First class.
The B777-200 have recently been refitted. The first class seat is a flat bed, and I had no trouble sleeping (I got an F seat when a 2 class flight was changed to a 3 class plane)!
The next best is probably the A330.
In last place is the older B777-300.
Cheers,
Rick