for what it's worth, there are two things to consider:

1. if you're careful about chain replacement, you'll find that the , chorus and centaur cassettes will last well-nigh forever.

2. i have a veloce 9sp cassette on my cyclo-cross bike and, after two years of racing on it it mud and rain and ice and snow, it has minimal wear. of course, i'm particularly diligent about cleaning my cross rig after every race and changing out my chain [a sram pc-59], so that probably has a lot to do with it.

in any event, the chorus, centaur and veloce cassettes are very, very durable, and they all shift equally well.