This thread is timely because one of my friends has been trying to shove DT down my throat lately (his favorite band). I agree with most of the posts here. To me it sounds like nothing but redundant scale runs that never end. There are some shining moments here and there, but overall it sounds like someone practicing etudes using the bass drum as a metronome. I'd much rather listen to Vai for technical mastery...even he can be a bit much, but he's much more interesting and varied.
Count of Tuscany is the exception. I love that song. Unfortunately, its the only song they have that rises to that level. I will say their music is good for background listening while working out or driving. But overall, inconsequential for any serious listening for me. And I did give them a fair shot with many listens.