Good stainless cages. I've found that the vast majority of plastic / carbon cages are bottle launchers here in the frost-heaved midwest. Having to stop, turn around and go get a launched bottle is annoying. Aluminum cages can be good but they make your bottles black and it's hard to bend them. Stainless cages don't mark up the bottles, you can tighten them easily for bumpy routes and they last basically forever.