I have a copy, and whilst I do not recall the price I know it is as you say
reasonable.
Just to add to what Jim said, it is correct it is only a tool. It gives you
the ways and means to analyse the performance of the spreadsheet, it is then
up to you to make it better. But unless you know where the bottlenecks are,
you have no clues as to where to start. I have met Charles Williams, the
author, at conferences where he has presented, and I think it is fair to say
that people generally felt that they learnt much from his performance tips,
much of which is documented on his site, or here at
http://msdn2.microsoft.com/en-us/library/aa730921.aspx
Improving Performance in Excel 2007