Sure, well I've flown the 777 in F many times. I usually go for one of the windows in the middle of the cabin, 2A/K or 3A/K. On the K side you have a shorter walk to the toilet (which is just in front of 1F) so if the crew are preparing the meal service (which can often be out on trolleys in the front galley) then it is more convenient. The other F lavatory is beside 1L near the cockpit door.
Not done EWR-LHR since they put the pre-flight dining in but have done PFD elsewhere. Whether you should eat there depends on your plans...it isn't fabulous food but does allow you to sleep as soon as you board.
"My first job was selling doors, door to door, that's a tough job innit" - Bill Bailey