Tal liked it:
http://www.chess.com/blog/Spektrowski/tigran-petrosian-foreword-to-aron-nimzowitschs-quotchess-praxisquot-1979
So does John Watson:
http://www.theweekinchess.com/john-watson-reviews/john-watson-book-review-107-of-eplus-and-chess-praxis He particularly likes the Sherwood translation version readable using the e+ app for ipads and iphones.
I had this book for years collecting dust and recently I just finished reading it. I had heard numerous pros and cons about this book. Going back about a decade at my first attempt to read this material, it was too advanced. But now that I'm able to understand it, the concepts are something I already use. I wanted to get a consensus on this book to see if praxis is worth the money and time. While I did find most of the book redundant to my knowledge, there were a few things that I found increased my knowledge. If anything it was an enjoyable read from a book written in the early 20th century.