Young British left-footed ever-improving player who's capable of playing both LB and LM to a good level and is quality on set pieces vs a sulky Frenchman with a bad attitude who had his best season 2 years ago?
That'd be the immediate perception of both players and why, I imagine, Zoggy isn't worth as much as Bale. Zoggy does have skills, but it's being overshadowed by all this other stuff.
N'Zogbia is improving, I'd say he's a better player than Bale is currently, Bale hasn't done anything this season whether he's been injured or not.