In reply to Jim 1003:
I can only say I totally disagree, but it obviously depends what sort of climbing you like. The granite is clean and solid on the whole, the protection excellent, the setting magnificent. Many of the climbs call for a lot of jamming so if this isn't one of your greatest accomplishments you may struggle with the grades a bit. The Dungeon is the biggest inland crag of worth in southern Scotland and has four pitch routes with terraces in between, but these don't really detract much from the climbing in my view. The descent is a doddle. It also has some very good single pitch climbs. It's a wild and remote spot and you are likely to have the crag to yourselves even on a weekend, but the downside is that you're on your own pretty much if you have an accident, or at least you will be for a considerable time.
I notice you list your main activity as sport climbing - sport climbing it definitely ain't. But if you love getting off the beaten track in remote wilderness then there's something special about the Dungeon.
The other crags I mentioned are also very good. Memorial Crag is set right on the summit of Craignaw with fabulous views of the Merrick and the Awful Hand. It's best described as a sort of granite Reecastle, short but steep with some brilliant routes. The Snibe is mainly single pitch stuff too, though there are good two pitch routes as well. It faces due south and dries quickly and is notable for have a considerable number of lower grade climbs which is not so common in Galloway, but also has plenty for the harder climber including the magnificent Beltie.