Better and worse than Trainspotting, the focus on one storyline as opposed to following the characters through a series of disparate events certainly appealed to me. 
The slow decline of Sick Boy and the upwards clamber of Spud along with the bursts of energy from Begbie and depressed straightforwardness of Renton all combine (with Nicky, who provides a refreshing newness) to create an insane but completely engrossing story that elevates itself above Trainspotting, as far as I'm concerned. 
The pacing dragged a little in some places, and Dianne felt like more of a throwback than an actual character, but the maturing of the book to be more coherent than its predecessor worked well, if perhaps not quite mirroring the lack of maturity from the returning cast.