I'm a big fan of Chambers. I've got 7 of the 12 editions of their dictionaries (and I'm hoping to get the current edition for an upcoming birthday), I have Chambers Words, Chambers Backwords, Chambers Word Lists, Chambers Word File, Chambers Anagram Solver and this - the 2001 edition of the Crossword Completer. I'd used the 1995 edition of Completer happily for several years until this edition came out. I then bought this and gave the earlier one to my daughter.
The 2001 edition is not an upgrade it's a retrograde. It seems to me that it has fewer of the more difficult words. And using it is not as easy on the eye - the word lists are harder to scan than those in the 1995 edition.
Having said that, this book is fine for finding most words that come up in crosswords. But if you're searching for the more esoteric words that you only find in the tougher crosswords (Azed, Beelzebub, Inquisitor, Listener, Mephisto, etc) then this one is really not adequate.
At one time books such as this had very little competition. Then electronic word solvers came on the market, and they keep getting better and better. The one I currently use is the Seiko 9000 Oxford Reference Library (also known as Seiko N681) - pricey but very fast (quicker and easier than searching through a book), pocket-sized and light to carry, searchable on a variety of criteria (anagrams, as well as completer mode - and you don't need alternate letters), and with a very good vocabulary. But there are still some words which you can't find with an electronic device but are found in Chambers.
So I've just ordered a replacement 1995 edition of the Crossword Completer from an Amazon reseller.