This translation of Kant's work is the standard text referred to by scholars writing commentary or analysis of the work.
This translation is written in clear and comprehensible English prose at least when you recognize that the ideas being conveyed are highly complex, highly complicate and highly abstract.
Norman Kemp Smith (1872-1958) was a Scottish philosopher who lectured at Princeton University and was Professor of Logic and Metaphysics at the University of Edinburgh. He utilized his knowledge of philosophy he brought this level of insight and knowledge to bear when he struggled to translate Kant's dense prose.
Translating this text is not merely a matter of accurately rendering and decoding one language into another, here it requires actually understanding the meaning of the words and the sentences that are being translated so as to render a comprehensible translation. You have to understand the whole book to translate any part of it.
Also, Kant is writing and re-writing this text as he works on it. Making another level of difficulty in translation. Here is brief few words by Smith from his translators introduction to this edition.
"Kant's German, even when judged by German standards, makes difficult reading. ...Many of the difficulties are due simply to his manner of writing. He crowds so much into each sentence, that he is constrained to make undue use of parentheses, particles, pronouns and genders to indicate the connections between the parts of the sentence. .... There are sentences which, to judge by their irregular structure and by the character of their constituents, must have owed their origin to the combination of passages independently written and later combined. ...he had, it would seem, in collating different statements of the same argument, inserted clauses into sentences that were by no means suited for their reception. In such cases I have not attempted to translate the sentences just as they stand. Were the irregularities retained, they would hinder, not aid, the reader in the understanding of Kant's argument. "
Smith overcame much to render this difficult work into clear but still dense English.
This the THE text to own and read if you want to delve into the depths of Kant's Critique of Pure Reason.
Good Luck.