I agree with Marcomo the F5 is very easy to GB and mine ran real smooth on the Atlantic in NC. The one thing you have to keep in mind is the GB can be considered Auto only to the effect that the machine will do it for you with the phase lock button or you can manually turn the ground balance knob for the GB setting. It is not Auto tracking where the machine tries to adjust on the fly. It takes user intervention to invoke the process. I two was a bit confused when I first read about the F5. None of the F series has ground tracking maybe a future feature. If you read one of Dave Johnson's early post he said it is pretty much a toss up betwee the F75 and the F5 on the beach due to some code that is buried in the F5. I do not have the F75 so I can not speak to that. I think you will be quite pleased with the F5 performance on the beach, a very versatile machine.
Take care
Bob