It's not hard to level somone to 100. Especially on your special days, and with the EXP multipliers. You can get some people to max in an hour or 2. You just need the right opponent. Exdeath is retarded as hell and is easy. He always spams the same warp move. Which half the time if your performing your special move, will get over taken instantly.
Probleme though is that at 100, the matches end too fast and get boring. Especially at the inner chaos levels where the enemies all have broken weapons and accessories. They can easily break you with 1 hit, and 1hit KO you less then 10 seconds into the match. Chaos himself also breaks the level cap and is at 110.
Also COSMOS is easily the best BGM.