I used the Gleim Sport Pilot kit, with mixed opinions. I think what I used the most was the CD with practice test questions. Using the book for that just didn't work for me since the answers were right beside the questions. The material was just
way too dry for me. It's written in outline form, like what an instructor would use to teach a lecture. It also can be repetitive. I'm used to reading engineering textbooks and the Gleim format just wasn't cutting it for me. It does have a logbook, plotter, E6B, and flight bag that I found useful though...
My solution was
The Student Pilot's Flight Manual by Kershner. Yes, it was primarily written for private pilots, but the 10th edition explains which chapters sport pilot students don't need to read. It's informative, interesting to read, laced with his dry humor, and most importantly, the information stuck with me easily. Not so with Gleim. It's a bargain at $25 (or cheaper at Amazon).
I ditched the Gliem books, read Kershner, then used the Gleim software for my test prep. Gleim tends to give the
what without the
why or
how.
Note that if you do go with the Gleim kit, you can save a bunch (~$80) by buying the version without their online ground school.