If you've not been in F on the 380 give it a try. Cabin is bigger so potential for less personalised service sometimes but you can try a shower at 38000 feet! You can also try the bar down the back which is good for stretching the legs. Other than that once you are in your suite I don't notice much difference. Flying from LHR you'll board straight from the lounge which is not the case at LGW.