I had my son start SM in Grade 3, and that was tough enough. If I could do it over again, I would have had him go back to SM2A and B and quickly work through the material introduced there.
He is now fine with SM and will continue into SM4 in the Fall. I am having him to CWP 2 this summer to solidfy the bar models.
I do love SM too, and am glad we are using it.