I'll describe how the tournaments at the UO go if you want. You don't have to follow these but I just thought I should show them to you.
First you have divisions based on difficulty. The last tourney I went to had a 5-8 division (Standard to Heavy, some lower Oni) and a 7-10 (Heavy to Oni, sometimes Nonstop) just to give you an idea. For one division, there was the placement round where two random people played one song (the same song for everyone) and they received their seed number like in NCAA tournaments. Everyone got in and it went #1 against #16, #2 against #15, etc.
Both players were given a piece of paper with five songs on it. I forget some of the details, but both players eliminate one song each. The higher seed chooses which side to play on (it does matter to some people). It's best two out of three songs but if one player wins the first two songs in a row, the third song is not played. Then there's the *cough* non-winner bracket. That's kinda self-explanitory. If a person loses two rounds, they're out permanently. Depending on how many people there are, some have made it best 3 out of 5 songs and single elimination. Once one division is done, repeat the same process for the next.
The "officials" based your score on some point system using the Perfects, Greats, etc. and not the score down at the bottom. Your total combo doesn't play a role either.
The bad thing about this system (IMO) is that it takes all day to finish a tournament almost. Wow, this took longer than I thought. O.o