I think classic is better for emulators.
It has a proper design specially for NES and SNES games when the gamecube controller feels awkward
I have a classic controller pro and a wired GC controller, and when playing in emulators or VC, i use the GC controller only in N64 games, for the rest i prefer classic or wii remote only.
for some wii games like smash and mario kart i think the GC controller is better, but Classic has more compatibility. Games like Last Story, Xenoblade, Rayman Origins, Pandora's Tower, Mega Man 10, etc supports the classic controller but not GC controller.