I've been on these now for about 6 months. These are a little skinny for roller derby. They are very good for latteral movement, but not terribly stable for giving or taking hits. I'm skating on slick concrete and the grippiness is just about perfect. If you are pretty much exclusively jamming, these would be a good pick, but if you intend to block too, you might want more wheel on the floor.

Ive been skating for probably close to about 4 years now and these wheels are by far the best wheels I've ever used. I can just think of something in my head and do it in the rink and it feels like skating on air. If you want to stop wasting time with other wheels then get these

As a little jammer i need something that allows me to grip corners and feel comfortable jumping around and dodging, this wheel does this even more than my old favs Radar Flat outrageous. The narrow width is awesome for quick cuts and manuevers. Only caution mix this wheel with a hard wheel. I had the Creeprs and Stalkers on and it felt like skating through mud on my home floor, great on cement but not wood. One set super grippy and one set hard.