The TH30 is great. Very versatile, lots of gain on tap and dynamic.
As far as I can tell its distortion channel it's similar to the DT but slightly brighter, with more high mids and slightly less over-saturated, so a bit more dynamic.
Still, is cr@ploads of gain and it takes overdrive pedals really well if you back down the gain a tiny bit too.
The clean channel is pretty controversial. If you're into fender cleans then its not for you but it's a proper British clean channel that's meant to be cranked. I love it, it's punchy and dynamic and although it breaks up at around 12 o'clock, its bloody loud.
Great for progressive rock or 80s metal. Think Tool or Porcupine Tree.