Belt drives are becoming increasingly popular on bicycles. Are they better than chain drives? The answer depends on your needs. First I will examine belt drives vs.  stainless steel chains using internal hubs. Then I will compare them to standard derailleur drivetrains.

Internal hubs: Belt drive vs stainless steel chain

Belts have a few advantages, they are cleaner, since they don't use lubrication. They last forever with a 100,000 mile wear rating. They are also lighter, keep in mind the weight difference depends on the internal hub. Shimano Nexus 8sp hubs have 5th gear as the 1 to 1 gear, while Sturmey Archer uses 1st gear ( 8sp hub ). This means you will be able to use smaller chainrings with a Sturmey Archer setup to save more weight. Also rust problems are minimized, stainless steel rusts, but not as bad as carbon steel.

However chains have advantages as well. The weakness of a belt is that they can be cut, this is a non-issue for chains. Additionally a chain drive system is much cheaper than a comparable belt system. Chainring/cog combinations are limited for belt systems, so getting the perfect gear range may be a problem ( especially for small wheel bikes using Shimano hubs ). Lastly belts require much more tension which makes the system less efficient. Overall belts have clear advantages over chains, however the stainless steel chains are still an excellent choice.

Belts vs. derailleur drivetrains

Multi speed drivetrains don't use stainless steel chains, hence the chains are more prone to rust. Boaters are wise to avoid this type of system. However a derailleur system is more efficient than an internal hub, they are cheaper, and easier to repair if a problem comes up. If money is a non-issue & your cruising on a comfort bike a belt is a great choice. On the other hand performance racers will prefer a derailleur system.