"This is a nice "progish" album. It is not a prog masterpiece, because you have to put it in relation to In Absentia and Lightbulb Sun. But it's definitely quite sophisticated, yet easy to listen to, never get's boring, and the melodies really grow on you pretty fast.
I can understand why some people call this alternative, as it has an alternative touch. But Porcupine Tree has always been difficult to describe, a quality that's not uncommon for prog artists. I'd say that this is a good starting point to get to know Porcupine Tree, if you don't mind a rough edge towards prog metal or alternative.
People looking for the Floyd centric mellow records which Porcupine Tree are famous for should go for Sky Moves Sideways or Voyage 34, Deadwing is considerably more heavy."