I have a brass roller rest on my bow right now. It works good for regular fishing shafts... butit doesn't play real nice with my Muzzy carbon arrow. (the carbon mag has aluminum outserts that hit the roller rest pretty hard)
I think I'm going to try the biscuit rest next.
Whitecloudhunter, AMS makes a rest called the Wave. It's an improved roller rest. I think it's teflon or nylon and it has sides so the shaft won't fall off. ('course, if your finger works....

)