If I can attend AnimeNEXT again this year (which is almost 80% sure) then I'm definitely going to attend the concert.
Miyabi from Berryz (and Buono!) is my favorite singer in Hello!Project. It's basically a once-in-a-lifetime opportunity to see her and all of the other lovely Berryz singers live!!!
They have a ton of wonderful songs. And I did hear about the Maiji Bomber flash mob. One of my friends is a bigger fan than I am!