I have the 1997 edition of Flowers & Silvers. I'm using that with a couple of other books which I was able to borrow from friends, including kaplan and the betz guide.
Flowers is far better than kaplan, in that it is much more concise, better writing, less extraneous material, and more understandable. Plus, flowers gets you really thinking in terms of proportionalities, where as kaplan just throws a bunch of formulas at you and expects you to plug and chug. The questions at the end of the flowers chapters are good and more realistic than the kaplan questions.
I will use kaplan as a reference mostly. Though, their chemistry section isn't too bad, so I may look at it more intensely when going over chem.
The Betz guide?? take it or leave it. I honestly haven't looked too closely at it.
Stick with flowers as your main guide and you won't go wrong, but don't be afraid to consult other books.
I am actually considering the examkrackers materials. I was at their website, and its pretty cool, you should definitely check it out and decide if its right for you <a href="http://examkrackers.com" target="_blank">web page</a>