If I might make a suggestion?  A lot of proshops or bowling centers have either one or both available, usually for the employees to read.  Try going to a couple of proshops and see if they have a couple of copies laying about that you could look at and form your own opinion of which one would be of more interest to you.  You're from Chicago, so I would presume that there would be a few proshops or centers that would have them.

Personally, I prefer BTM.
--------------------

I just want 2C was'zzub.
____________________________________

I am the SGT Schultz of bowling.
"I know nothing!"

BTM is better in my opinion. It is very indepth about mental and physical games.

The ball reviews are very good as well. BUT take them for what they are worth.....read what they say about the ball, but the numbers not accurate all of the time.