Designer Jeans vs. Generic Jeans?

For the longest time I have always bought generic jeans because I am frugal. Recently, however, I broke down and took the plunge and bought a pair of jeans from buckle. I've noticed that the buckle jeans fit so much better than their generic counterparts. Also, the denim seems to be cut more precisely then the generics. So, the last time I went shopping, I tried on a pair of Banana Republics and J Crews. Same result. They looked great on me, just as good if not better than the buckles. I didn't buy them, but I went home and tried on the generics again. Not nearly as comfortable as the buckles. All this time I thought the brand names were more expensive because of the names, but now I tend to think differently. So...is it just my imagination? Has anyone else noticed this?