I bought Silman's book over the weekend, and so far it looks about as comprehensive as any endgame book could be. I also trust Silman's writing due to his other books. I would say his book is suitable for most anyone, so long as you have a reasonable foundation already. He covers the most basic endgames all the way to the more advanced; not surprising considering the title...
Essential Chess Endings by Howell comes very highly recommended. its a small book perfect for the tournament player with limited study time. With careful review, anybody with the basics should be able to finish this book in one or two weeks. It covers everything, including basic mates and a clear explanation on how to mate with B+N+K vs. K. This book will take you all the way to 1600-1800. For a more thorough review take a look at silmans or Amazons.
"Endgame Challenge" is a book of puzzles, so if you don't already have some endgame knowledge you are probably not going to be able to solve many of the problems in the book.
For a 1300-player, I would recommend "Pandolfini's Endgame Course". Also excellent is "Practical Chess Endings" by Irving Chernev. A good book if you don't mind descriptive notation.