Another fantastic translation by the great Magnus Magnusson.
The intro itself is worth getting this particular volume. Well researched, well laid out, a pleasure to read.
The two sagas are themselves some of the best saga reading I've ever done. Brief but so revealing!
I recommend reading them first, then Landnámabók and Íslendingabók, for background, then whatever else one wants to read: Njáls saga and others.