Read The Wasp Factory when it first came and really loved his other early work, really enjoyed the rerun of The Crow Road, miles better than any of the other adaptations. Not really written anything decent since Complicity, imho.
The Steep Approach to Garbadale is getting back to his earlier form but a little run of the mill for my tastes but it is worth reading just for the description of the suicide and was a huge improvement on the awful era of Song of Stone, Business, Whit etc. Never really got on with his Sci-Fi stuff either.
Saw him do a Q&A at a festival last year and was really impressed with his honesty and openness about his writing (and his loathing of Mrs T)
Strangely, I am looking forward to Transition, he may be revisiting old themes but at least he's revisiting the good ones. And the early reviews I've read and comments from friends who still do the hardback thing have been very good.