Belts have always worked for me. The only problem I've had is that once, my belt did not show up before a match. I keep pretty good track of my belt rating and haven't noticed any discrepencies.
Here's what I have figured out:
- Ratings span from 1-99 (with the exception of Black, which can go up forever)
- Everyone starts off at Blue with a rating of 50
- Belts go upward from Blue to Green, Purple, Red, Brown, and Black
- Belts go downward from Blue to Yellow and White (if you see a White belt, he/she really sucks)
- When you get over 99 for a Belt, you instantly jump up to 50 with the next Belt. This allows naturally good players to advance faster, and prevents a few fluke losses from dropping you right back down to your previous belt
- If you beat an opponent with a higher rating/belt than you, your own rating will go up more than if you beat an opponent with a lesser rating/belt
- The opposite is also true: a loss to a lower-rating player will cause yours to drop more than a loss to a higher-rating player
- In an FFA match, 1st or 2nd place will raise your rating; 3rd or 4th place will lower your rating
What I have not figured out is exactly how much the ratings are affected by a match and what minor specifics determine the rating. I remember in one match, me and my 2v2 partner were Green belts and we faced Black belts. We lost, but it was a close match (we only lost by 2 kills), and our belt ratings actually went up 4 points. I'm not sure if kill counts or scores have anything to do with belt ratings, but it would make more sense if they did than if they were entirely based on who did better than you.
