I went to Acen a few years ago with a couple friends. DEFINITELY get there early for your badge. We had to wait in line for about four hours to get ours. It was getting so bad, we became close friends with the people around us in line =w= ...Aaaaand we drew graffiti on the floor ._.
But, after the long wait, the convention itself is pretty awesome. There's a lot to see and everyone was so nice. Vic Mignonga was there, too =w= It made Kaylyn happy XD I was next door at the J-Rock Power Hour lol. I met really cool people at that panel, too.
Unfortunately, I don't live close enough to make it a yearly thing. I'm in Missouri [which I'm only six hours away, but then again, I'm SIX HOURS AWAY]. If I lived closer, I would definitely go again, it was a lot of fun, and I would recommend it to anyone else who wants to ^^