Jensen Grammar Users Question

I am looking ahead and thinking about using Jensen’s Grammar and Punctuation.

But right now we are in the process of using a program called Grammar Key http://www.grammarkey.com/

I feel like they are teaching the same thing and wonder if it is really necessary to keep doing it over with a different program?

If someone who has done Jensens could just look over the little information and maybe ask me a few questions about grammar key you might be able to help me figure out if they are the same or it’s worth it to find a set.  I appreciate your time.