In reply to nclarey:
At the moment, for anything approaching comprehensive coverage, you'll need both books because the Ground Up one was never designed to cover everything. It's a kind of interim guide.
However, if you're content not to visit some of the honey-pots and not to have descriptions and grades for easier routes on some of the crags that are included, and if you prefer mid-grade to harder routes, then I'd say the Ground Up guide is all you'll need. It's attractively produced, makes you want to climb and has lots in it that's not in the Cicerone book.