Valhalla has the wow factor for me, whilst Hex has the atmosphere, and I'd go as far to say that I prefer rides such as Duel, Hobs Pit and traditional ghost trains (obviously not the ones on the back of a lorry but the amusement park/old style ones).
I'm sure plenty of people will be amazed by DBGT, I'm not saying that it's a bad attraction but whilst I found it enjoyable it's just not really my cup of tea.