I used the first two EG texts with my boys when they were younger (2nd, 3rd, 4th grade.) Alas, when we got to year three, we discovered the brand new textbook we had purchased was missing the first 24 pages. I wrote to the company, but never received a response. In the meantime, we discovered First Form Greek through Memoria Press, which both boys took this year (grades 5 and 8.) We were happy with the class, which is advertised as being worth one high school credit. The only drawback is that MP does NOT offer year two of Greek.
I recently discovered that The Potter's School offers three years of Greek, and the teacher uses Machen. It is even more aggressive than Memoria Press, so I wish I had discovered them sooner. He makes it almost all the way through Machen in one year. I'd have the boys take this class in a heartbeat if it was offered at a reasonable time for west coast time zones. For some reason when I suggested a 4am class an insurrection ensued. If anyone knows of an online seminary or college course using Machen, I'm looking :)