The build along Rob has here makes a good one. Whatever kind you choose though needs to be the narrowest at the bottom, coming up to a larger top. I had one made to the build alog specs out of vegetable tanned buffal hide. I had an adjustable belt added and an outside pocket for file, stringer, extra string, roll of black tape etc...
Listen, all leather will break in to fit your back if you wear the thing correctly. It should be snug and it will comfor to the natural arch of your back which holds the arrows tight and rattle free. Even allowing you to bend over problem free. So material isn't any more important than proper fit. Wear and break it in correctly, you'll love it.
I would strongly suggest you looking into the templete posted here. It makes a great quiver if you substitute their strap for a strap type. Add a little pocket and yu got the real deal. I try and post a pic f iit. God Bless