What is the difference between a Thule and Sport Rack roof cargo box?

I'm trying to figure out whether the Sportrack make is as good as the Thule make. There seems to be a large difference in price.What is the difference between a Thule and Sport Rack roof cargo box?
They're just different brands.What is the difference between a Thule and Sport Rack roof cargo box?
I'm not certain on all of the specifics, but Thule has been around for years, make great products and is usually the first brand I think of when someone says aftermarket car accessory... bike racks, ski racks, luggage, etc. I personally don't need or use one as I out everything under the tonneau cover on my pickup truck, but I hope that this helps some.