1) I don't know the other system so I can't tell you the difference. However, it's nice to see you are comfortable returning the material. With a simple phone call you can get LSC to extend the trial period to six months, and I would suggest you do this.
2) Both formats have all of the information you need to master the system. The course is more hand holding and has some confidence building exercises. Many people who post seem to feel they are missing something by not having the course. So one main advantage would be acquiring greater confidence, and this is important for the system. The reason I bought the course is because I thought it would be faster than reading the book, and the cost wasn't too prohibitive.
3)I think that you will find the PhotoReading Whole Mind System (PWMS) very valuable for reading Economics material.
I wish you well in whatever path you travel in the future.
Iam2 
