I have a Mission Workshop Vandal (as does my wife) that is now 2 years old and still hasn't let me down. I use Arkel saddlebags on my Vaya these days, but my Vandal is my goto bag for everything from a 2 week trip to California to going to the grocery store to haul 3 bags of cat food and beer.
The lifetime warranty itself means the price is good - the fact that it is made by people in the U.S. who need to have a working wage that allows them to survive is better.
Cheap usually means collapsed buildings down the road in third-world countries.