I am a Sabaton fan because of their live show.
I got my wife meet & greet tickets for Nightwish, with Delain and Sabaton opening. We got to meet Nightwish(got pics, autographs), then saw the show.
Delain is not my thing, have to say though, their original lead vocalist, Charlotte Wessels, is a skilled singer and preformed well live.
Then Sabaton came on and about stole the show. They came out on stage with loads of energy and kept it going through the whole set. They play incredibly well live and were interacting with the crowd(not to mention making fun of themselves quite a few times) almost non stop. The band knows they need to bring it live, and they have never failed to do so the three following tours I saw them on.
Nightwish was excellent and put on a great performance, but, most people walking out were all saying Sabaton were the surprise they were not expecting.