Used it with my 2 kids and about to start using it with our # 3
It is a great alternative to Classical Doman dot flash cards method. The biggest deciding factor for me was... TIME AND CONSISTENCY, as much as I was determined to do Doman Math with my first girl, being a new parent I simply was not able to prepare all the equations, all the card rotations for each session and do it consistently. So for me, it was an excellent alternative.
From my
personal experience it works the best up till about 18-20 months. Once my kids were about 1.5 years ( and we finished majority of LM lessons) we were ready to move on to other math activities ( we were still using LM occasionally and for specific tasks, but not as a curriculum at that point). So we would move on to Marshmallow Math activities, some RightStart Abacus activities and lots of logic math exercises (tangrams, critical thinking, reasoning, algorithms)
I believe LM was a great fit for us to be an introductory curriculum, which helped me to stay consistent and to not stress it, when my kids were just introduced to math concepts. And I think it gave them a great head start, even though we never normally tested them. My little girl is 4 now, and she is fluent with her numbers up till 100, can recognize and compare numbers up to 1000, we are working on math patterns now, and solidifying math facts before moving on. My son is 2 yeas old -- he is good at critical reasoning for his age, does creative thinking exercises ("sort not red and not oval shapes into the first ball, and not square in the second" , etc), he operates numbers under 10, counts till about 20, does beginning abacus. Our baby is about to turn 4 months and we will be starting on LM with him around that time!
Why dont you download it and try it out for yourself, it will help you to see if it is a good fit for your situation.
I personally decided to stick with classical Doman red dots for the 1st 20 days of the program, so I created presents for myself, then we switched to curriculum.