The case wrench may not be big enough for today's fat-faced watches and I had to leave the thumb screw loose as I angled it a bit to loosen the case on my widest Fossil, but it works and if you are somewhat gentle with what you are doing it won't break.  I've read many reviews talking about how it the tools break on the first try and my response is well... don't force it.
It does what it is suppose to do and it worked for me.