Quality control at Subway seems to vary widely between stores. Some Subways I've been to are consistently great - clean, with helpful staff, fresh bread and fresh toppings. But a lot of other stores have stale bread, zit-faced 16 year olds who don't give a shit making my sandwich, and a dingy appearance. I've never had bad bread at Quizno's, but it seems like half the time I go to Subway I get some crusty stale loaf that ruins the whole experience.
Yes, prices at Quizno's are higher than Subway, but you get a bigger sub with fresher ingredients. Every Quizno's I've been to has had consistently high quality.