There are so many gyms that you could class as the best FC Gym, many of the above being among them but there are so many factors in which would sway ppl's oppinons.
I believe that it is down to the trainers and if your trainer is a dedicated person (and likeable) who puts all their time in as you do with fight training, you will become a good team and potentially the best FC gym around. I think many gyms speak for themselves and those with champions must be doing something right to produce such talent.
I also feel that being trained by a champ itself helps implicitly as they are aware of what work goes into being the best.

DanUK:-I am now fighting out of PW Kickboxing Academy (Paul Wiffen) but thanks for the mention. ;oD