Easy Grammar presents english concepts in a workbook style approach. Many parents like the Easy Grammar books because the lessons are generally quick and straightforward. Both teachers guide and student workbooks are available. However, the teachers guide has both the teachers notes as well as all of the student workbook material within the guide- so it’s an all-in-one. The teacher’s manual contains the student pages exactly as they are presented in the student text- so you could decide if it were important for you to purchase the student workbook or simply make a few copies from the teachers manual as needed.
In our family we are currently using the Easy Grammar Plus (for my 5th grader). Certain concepts will probably be skipped until 6th grade or so as the material can get complex.
So far my daughter thinks it’s fairly straightforward, but a little too cut and dry. Then again, we hopped right into the Easy Grammar system at one of the more advanced books, so I don’t know if having started at a younger grade level will caused us to have more experience with the system, and perhaps like it better.