My passion is for guitar and other stringed instruments and I don't have a preference, so I teach both electric and acoustic. I prefer steel and nylon acoustic guitars in the hands of students, and music that suits the instrument, but there is so much possible cross-over material that I rarely distinguish between acoustic and electric. For classical students, who are few and far between in my market, I naturally prefer a nylon strung instrument in their hands and mine. If I specialized, I'd almost starve to death. Many of my students will alternate between electric and acoustic guitars, and that is as it should be, in my opinion. Variety begets knowledge.
I've used the Troy Stetina books, but generally I use student favourites to achieve their goals, as well as my own program. I find that the Mel Bay Guitar Journals and Mastering The Guitar series suit electric and acoustic.
I teach both electric and steel string acoustic guitars in the jazz, blues, rock, country and folk styles. I use the book that I wrote, The Guitar Lesson Companion. It covers all the fundamental concepts, contains plenty of exercises and it was designed for students who are studying with a teacher.
Guitar Instructor at Seattle University
Free Lessons: http://www.youtube.com/leadcatpress
On the website for your book, you state that you feel that electric is better to learn on. I know that there are many reasons to go either way, but I think that acoustic is better simply because it IS harder. (And a quality set-up will fix most of that anyway.)
You lay out a 3 year plan on the site. Is your book designed around this idea?
I have a different viewpoint. Guitars that are too hard to play can lead to discouragement (at the least) and even serious injury. I think it's important for students to have fun making music right away, and I have found that students who have a guitar that fits them, is easy to play and that they like the look/sound of usually practice more and get more enjoyment out of lessons and music. I never tell a student not to start on an acoustic guitar, but I do outline the challenges and explain the experiences I have had in my teaching studio.
I use The Guitar Lesson Companion in a 27 week course I teach at Seattle University where the students are committed to practicing about 10-20 minutes every day. Each "year" listed in the blog is covered in a quarter (we have 3 quarters in the year.) I have a "Suggested Weekly Lesson Planner" that comes with each book ordered from the website that details the topics, book pages and corresponding lesson videos. Please check out the table of contents and email me if you'd like more information on how I break it down, of course other teachers have their own system when they use it with their students.