In reply to tompilgrem:
Gary Latter's has more photos, and some newer stuff (like Erraid), and is split over two volumes, North and South (so you may want both volumes depending on how widely you want to travel). It doesn't have any lowland stuff. The photos are nice for getting inspiration of where to go.
SMC's is only one volume and covers more of the country (lowlands - maybe Aberdeen sea cliffs?)
There is also Kevin Howett's Rock Climbing in Scotland, but I don't have that, so not sure how it compares.