This was first time seeing any of the bands. I was very familiar with Gamma Ray and Helloween's work, not with Manticora's.
Manticora was alright. Bass player was badass. Vocalist was active and tall. The music sounded somewhat like Stratovarius or Blind Guardian. There were a few good parts, I may get one of their CDs.
I recognize GR as one of the solid if not top power metal bands. They probably moved half a step up in my eyes. They put on a very very impressive show. Kai Hansen was funny, could sing much better than I expected live, and play like a madmen. Metal cliches were strong, especially I got a kick of the Manowarian finale.
Helloween is like my top 12th band, so my expectations were high. And they delivered. Intro with Helloween was great, then it kinda slowed down for me. They have a lot of great songs, so the second half of the show was awesome. Andi Deris is quite interactive with the crowd, with almost a crazy Dickinson/Lee Roth (not as good as either of course) vibe. He sang pretty welll too, especially the latest material. The highlight was of course the grand finale with GR joining them on stage for Future World and I Want Out. 4 guitarists and 2 bassists kicked ass!
Kai and Andi shared vocals, and at this point the whole venue was finally fully involved.
I feel that it was totally worth the 4+ hour drive, a short sleep and a pissed of wife, as I write this from work.