You could make the arguement Discraft has the best mid selection in the industry, period.
Their entire mid line up is solid:
Stratus
Meteor
Buzzz SS
Comet
Buzzz
Wasp
Hornet
Drone
... and don't forget the Nebula (alias Buzzz OS).
Whereas Gateway's bread and butter is the putter, I think DC's is the mid. As for the rest of their line...
Their putters are quite good too - Challengers and Magnets are pretty popular (even if they don't sell as well as Aviars or Wizards), and the Focus and Banger have their fans as well.
Some people like their distance drivers, some don't, but they do OK with their the Nuke (+SS & OS), Surges (+SS), Avengers (+SS), Force, only time will tell about the Crank.
Despite having some good molds like the XL, XS, Predator, Stalker... fairway drivers has to be where they lose the greatest marketshare.
Id throw a Zone in the mix, but I dont think it is even debatable... Innova has the best full lineup of fairways, Leopard, TL, Teebird, Firebird, Eagle, Viking, Whippet, Viper but that isnt what I read as the point... Discraft has the best mids but how are they promoting that. Its tough Innova got promotion with their drivers and blizzard plastic with the world record... mids arent flashy..like putters or drivers...