Another vote for the Costco bag.

I picked up the 22" after my el cheapo $10 roller finally started showing age. I never knew what I was missing before. It rolls with minimal effort over uneven surfaces and takes corners well without tipping.

Many times I check it as to not deal with the hassle of dragging it around (most of my flights are connections) and it still looks and feels new. The zippers are high quality and the wheels are the "Rollerblade" type.

Also, as others have mentioned, if anything DOES break on this thing, Costco will take it back and give me a new one no questions asked.