This book is exactly what it says on the tin - a point by point response to Locke's Essay Concerning Human Understanding. Consequentially it's pretty pointless to try reading this if you haven't already read the Essay. It's interesting from the point of view that it's virtually the only example of one great philosopher making a detailed reply to another's work, and that besides the Theodicy it's Leibniz's only full length book. The problem is that detail however - this is only marginally shorter than Locke's Essay, and the problem of the Essay's repetiveness is exacerbated here, as Leibniz seems to say the same things over and over again. The dialogue form is also disappointing as Leibniz puts in very little effort to make the speakers even remotely realistic (although some claim that the work is, stylistically, unfinished, which accounts for that).

In terms of the edition, it's much like all the others in the Cambridge History of Philosophy Range, which is to say, very nice, with a helpful introduction.

Overall, I'd say this is a book for study, rather than reading for enlightenment. For scholars of Locke and Leibniz only.