You'll have to judge the gear ratio for yourself, but as far as brand of cog goes...I've tried Dura Ace, Miche, Surly, Soma, EAI, bolt-on Tomicogs, and a variety of cheap stamped cogs. The cheap stamped ones I have tried wear faster so I would avoid those, but the CNCed cogs are all basically the same. Look around the web and find the best deal.