There's some other threads about belt drive on here. I've made some comments about the Gates Center Track.

I have a freewheeling Spot steel hard tail single speed mountain bike that I really enjoy riding. It does the job well.

But my experience is that over all chain drive is better. I ride chain drive single speeds as well on some of the same trails.

The reasons are:

​​​​​​Chain drive offers a wider variety of ratios for less money. Chain drive is actually a bit easier to work on when you actually do any service. Granted, it is true that the belt doesn't need any attention once it is properly installed (and tensioned).

​​​​​​My belt drive bike is not as quiet as my chain drive single speeds can be (when they properly maintained). There is a sort of buzzy sound at high torque which can be temporarily silenced by squirting water on it, or by using silicone spray belt dressing. I did try belt dressing for a couple of years on a regular basis, and it works, but it seems like a defeat to use it (and it would dry out on long rides). The buzz is only there in very low humidity. If it is damp outside there's no noise. I've tried various tensions and have not been able to adjust it away. It seems like certain kinds of trail dust are the cause (but I don't know if that's true).

So for me the belt drive SS MTB is incredibly excellent for wet rides as the bike is quite impervious in situations where the chain drive bikes would be in dire straits.

Appreciate that this is my experience and opinion.

In the belt drive favor, the response and feel is better than a chain. This is a quality that I separate from the freewheel engagement (Chris King on this build).

I've accepted and read that the belt is less efficient than a chain. However my experience is that the difference is so small that it doesn't make a big difference (to me). I think the air pressure in the tires is an area with much greater potential efficiency loss.

​​​​​​My wife has a belt drive utility bike with an Alfine hub that is perfect for those around town trips for groceries etc. It's ideal really. That bike is just ready to go all the time.

I still ride my belt drive MTB a lot and love it. Sometimes I think about going back to chain drive on that bike though. I won't, since I have alternatives. But if it was my only bike - that bike would be chain drive.