[Sachiel7]

Well, my team had an interesting experience with using belts this past year....
We had many problems, however I'm not 100% convinced this is because of belts.
In my opinion, chains are alot better to use in FIRST, you just MUST spend plenty of time making accurate measurements and making sure everything is lined up exactly perfect.
If you are going to use belts, Make sure you know the size of you belt and order it a good time before shipping. Also, make sure you get extras.
The main prob. with Belts is that you pretty much have to buld a gearbox to go to a shaft to hold the Belt Drive, and that can be pretty painful. you then have to worry about where all your resistance force is going, and need to find a way to keep most of it off the gears. Also, you have to find a creative way to do this with keeping tension on the belts.
But, If you can do this, good luck.
At least with chain, if it breaks, you can fix it. With belts...you'd better have an extra. In fact, this past year, we found out on Day 1 of our reigonal that our leader had ordered the wrong size belt for 2 motors of our dirve sys. Well, we tried to cut them down to size, but they just broke in the first 5 sec. So, we had to scramble the rest of the day to order in the right size. When we finally did, we had to take apart our robot to put them on. During the next match, we found out our tensioning techinique stank, so the belts (and gears) stated happily ripping themselves apart.
So, just a few words from experience.
(My team hasn't used chain yet, but we plan to this year, after talking to other local team, they prefer chain over any other type of drive)