Vortex Racing offers a contigency for using their sprockets. This is the main reason I bought a couple form STG. As for the overall quality, they are good but not great like others (cough*Renthal*cough). BUT...when you race a 1000cc superbike with a 520 conversion, you tend to chew up sprockets faster than your average street rider. This is another reason why I bought them.
As for the actual fit/finish. I rated it 3 of 5 (average). There where some burs and dinged teeth, but when you look into the way I use sprockets and bounce that off the cost, these are worth the $50 cost all day long.