The lunch/dinnertime a la carte food and wine in the F lounge is genuinely quite good, and is definitely worth the USD100 difference if you will be there during meal time. (USD100 really doesn't buy you much food and alcohol of similar standard in town!) But I don't think I would do it if my stay was only during breakfast time.
And if paying extra for the F lounge, I would definitely trek over to Concourse A.