Look at cost of ownership
Belts don't last long and you still might never achieve the flatness that stones provide. Also, the speed of sharpening with power also increases the risk of burning the blade. Add up the cost of belts and consider the time to install them and you will probably fine that stones are cheaper in the long run. Personally I like the quiet and satisfaction of sharpening by hand. I use both sandpaper on a granite surface plate and the Shapton waterstones. I use honing guides. Just starting to get into edges with shapes (like gouges, etc). Got the new DMT Diamond Wave 1200 from Woodcraft but have yet to use it. I'll try it out tonight.
Eric