I think most people prefer the FN over QC because the QC cages are quite industrial looking, and the FNs could be said to look more like "furniture".
I have 2 Quality Cage Townhomes, and I absolutely love them. I love my QCs because they're sturdy, secure (there's no way the chins are strong enough to open the spring locks), and easy to clean. Also, if you ever need to move the QC cage will fold flat for easy transport.
I would not recommend Martins cages (no offense to anyone who has them). My brother used to have one for his chin (now my chin), and it just seemed flimsy, and it was also a pain to clean because the entire cage had to be lifted out from the pan to clean it. Because of the size of the doors, and the layout of the cage it was also not easy to get inside the cage to clean or even to grab Max. Also, the cage was NOT easy to transport, since it didn't fold flat.