My child goes to MJA and we love it! The teachers are caring and working independently with each child. The school's curriculum is up to date and rigorous with the individual child kept in mind. The school has recently added 2 book clubs, one for grades 1-4 and one for grades 5-10. Our son loves the book club! They also have intramurals for grades 5-10 and a very active Student Association. They also offer an upper grade history trip or mission trip every year! We love MJA and will keep our son there throughout 10th grade.
I attended Memphis Junior Academy myself, and I will say it is an 'okay' school. I think after eighth grade, that's all it's good for. The curriculum is just not that challenging. But one thing is good: the religion & spiritual things are excellent. So, overall, I would give it (1-10 scale) a 6. They can do much better.