Different strokes for different folks. I am not a fan of Kirby art, the FF, Andy Kubert art or Gambit. I stopped collecting Uncanny at issue #180 when I thought there was too many Mutants running around to keep track of.
having said all of the above, and all things being equal, I would take the FF cover over the XMen cover without hesitation. I would even do so , again without hesitation, if someone offered the xmen cover + $75K in exchange for the Kirby FF. quite frankly, I don't think Gambit is as big a deal as a few vocal folks are making him out to be.