You'll have to excuse me, I just got back into Pokemon after years away from it, and so I'm a n00b as to anything past Generation II.
So, do I get anything for getting through all the Frontier Brains? Other than Symbols and impressive records, I mean. My brother says you apparently get a rare Pokemon (I've already caught Sudowoodo and Smeargle), but he was telling me through hearsay of his own, and we all know how accurate the spoken word on Pokemon tends to be.
In any case, I'm having serious trouble with it. It's taken something like this for me to realize how badly I've relied on having my PKMN at higher levels than my opponent's to beat them. Now that the levels are all matched up, even with all my PKMN being well enough in the strong category and beefed up using all the Calcium etc. they can take, I've still only managed to defeat Pike Queen Lucy, and only gotten about halfway through the Arena, Tower and Palace before getting brutally pwned. I made it all the way to Pyramid King Brandon once, but he drove me into the ground. I'm sure you've all had frustrating moments like this, but that was sure a doozy. I actually had to use a breathing exercise to calm myself down after that.
At least items are disallowed, 'cause I reallllly hate it when you whittle an opponent down into the red, and their trainer uses a Hyper Potion on it.