I don't know what all the bitching about is. I think they sound pretty good. I am not a big fan, but I have heard many songs by them. They have good stuff. If you don't like it, don't go.
I haven't seen DF since 2006 or so, and between their obnoxious fans and less than impressive performance I came to hate them.
BUT...
Their new album is absolutely killer melodic power metal, and I had to miss both runs of the Kamelot/DF tour this year. If nothing else, I'll be interested to see how different they are live.
ZP Theart did act pretty arrogant live, it actually makes their first live album a little offputting. Plus they were usually drunk back then. They play much better live now.
I'd love to see ZP Theart live with his new band, Tank. Their new album, Valley Of Tears, the first one with ZP on vocals, is killer and one of my faves of 2015.