Leveling TC

Is there any discernable difference in all the plastic leveling blocks? I've seen Lynx in action, but have noticed that there are quite a few brands out there now, some less expensive than others. I am all about saving a buck if I can get away with it, but if someone can explain to me why lynx levelers are roughly $15 more per 10 pack compared to the Camco equivelants, I'd gladly pay a little more for the better quality, but if they are essentially the same quality, I see no reason to pay more for a similar product.