I just got finished on my first Level 99 Dark Note which was pretty sweet. I was shocked to find an entire game mechanic appear when you reach Level 90 onwards (the yellow sliding arrow ones now spinning as they go towards you) so it took a little longer to get used to that to finally get to and finish a level 99 Dark Note.

Has anyone else done that yet? And if you haven't then what is the highest level of Dark Note that you have completed?

Currently in the 70s.  After unlocking Faris, Yuna, and Ashe one after another, I'm leveling them up now on lower level dark notes.  For some reason, even playing a high level dark note gives me significantly reduced EXP with those three around (probably due to a general inability to kill enemies in BMS) so it's not worth it to keep trudging off ahead just yet.

72, so far. I got stuck on 73 because Jenova is a damn hard song at that level. I have the character levels to unlock a 95 or so, and could probably do so if I practiced for a bit. But for now I'm focusing on unlocking characters, working on a single Dark Note that has given me all 8 Rainbow Shards, 6/8 Green, 1/8 Purple, and 2/8 Navy (the last two are boss #2).

60 something. I don't really enjoy them at that point though. I barely made it to the end of the battle section. (seymour I think)

@Blind_Evil: If you having trouble getting the Boss #2 to appear (as you seem to imply) then my advice is to put your slowest character first in the FMS (or if you really know the songs, put in a low level character in that place with low agility) since it actually isn't about doing well or doing badly in the FMS to decide whether you get the 1/2 or 2/3; it's actually about distance and passing the sign that says 2/3 on the road in the FMS. This means you will likely not go the distance required and then in the second one you simply have to do well and the boss 2 will appear.

@Turambar: I found that levelling up character individually when you unlock new ones is more efficient, especially if you have an EXP Hound Ability Item to put on them (this means they get all the experience so if the other 3 are maxed out then none of the Exp is wasted), this allows you to continue to do high level songs because the other three can make up for the low level character, and since you are doing high level ones (as long as you are doing well on them) then you will get more Exp. Doing it by this method means it is quite likely the low level character will level up at least once every song.

@GunstarRed: When I find ones I am bad at I find simply setting up my party with a healing set-up and possibly an item to heal if it goes badly (I end up with loads of Potions so I just leave them equiped when I am not trying to get a high score on a level; if I want to do this I go for the stoic bonus but on Dark Notes it actually doesn't gain you anything to go stoic). This way I can sort of brute force my way through songs I am bad at and then I can enjoy the ones I like (it also means I can clear a Dark Note and move on to the next one pretty quickly so I can do a bunch at once and since they slowly get harder/faster then I end up doing well on levels I usually expect to do badly on since they are such a high level due to me getting used to the speed previously meaning it feels like the difficulty is going up slowly like a normal games difficulty curve rather than what I found when I beat one then later went back and found I was horrible at it due to sort of forgetting the speed).

@Dixavd: I dunno, I've never, ever seen boss #2 appear if I didn't pass the sign. I'll give it a shot though.

I've gotten as high as a lvl91 Dark Note (and was startled by that mechanic as well), but then got distracted by going back to Challenge/Series mode and finishing up the Ultimates.