We just hit both this week and both me and my S/O liked the FL much better. AMEX was too crowded and while the food they had was quite good, the selection was severely limited. This always is the case with AMEX IMHO. I feel like AMEX is great when you want a full meal, but it's terrible when just in the mood for snacks.

We also liked the champagne/sparkling wine MUCH better at FL. We did not have access to FFD but if we did then it would have been night and day with AMEX based on my FFD experiences at LAX and JFK. For red wine, I'd say comparable but if forced to choose, I'd again go with FL.

Also, overheard that there is a secret champagne available for AMEX Black Card members. I wonder how it compares with the kind-of-crappy sparkler they were serving.