I bought this book to check my reading of the original on occasion when sentences were particularly convoluted (Sade writes in an ironically formal Ancien Régime style of French). I was astonished to find gobs of mistakes in this English translation. I'm not exaggerating, there are three mistakes in a single paragraph on the latest page I've read, p. 151, the one starting with "Yes, Chevalier, you are saying...". Here they are to give you a taste.
1) "within you" : Should be "within me"!
2) "Do you smother remorse through your principles when you feel its goads" : Should be "May you smother (or just smother) ... if you ..."
3) "Will you manage to repent a misdeed of indifference that you have thoroughly penetrated?" This sentence is nonsensical as it is translated! It should be something like : "Could it be possible for you to repent an act being thoroughly penetrated by an indifference of it?"
This is only one paragraph. There are countless other mistakes strewn about.
I'm not familiar with other translations yet, but if you are concerned about fidelity to the original, I would advise you to steer away from this one. In spite of the fancy cover, the contents are greatly disappointing.
That said, if you're only interested in the sex tableaux, fidelity is not necessary and the translation is sufficient :-P