I subscribed 2 years ago year, but didn't renew my subscription. It's not a bad publication, but the material didn't do a lot for me.
The articles seemed either too basic, or went into too much useless technical minutia. The ball reviews usually didn't give me the same insights that I get with BJI. I'm stating this from the viewpoint of a ball whore reading reviews of balls I already own, and in many cases scratched my head at their assessments. Ditto on their ball comparison tool. It missed the mark on many balls I owned that I compared.
Again, your experience may vary. It's certainly worth giving BTM a try.