When you pay for a more expensive tube, you are either paying for a lighter weight, less durable, racing tube or a heavier, more durable, commuter/touring tube. I have a Specialized rear tube and a Kenda front tube. Both hold pressure very well, but the specialized tube had a stickier (and higher quality feeling) rubber, it had ribs on the tube (Not sure of the correct function, but it's an extra feature), and the valve stem has the threads for the lock nut (which the Kenda does not) which is VERY helpful when inflating a dead flat tube. Kenda tube was $2 cheaper though, but I patch up tubes until patches overlap patches.