I am only familiar with ALEKS for 5th grade, 6th grade and Pre-Algebra so I can't really speak with authority for the lower level stuff. I am assuming that you are homeschooling a first grader, so I would say probably okay for that purpose as long as you supplement with non-routine problems and with problems that require showing work and writing, particularly as he moves up the curriculum. ALEKS is a good resource but I would hesitate to use it (by itself) to argue grade level achievement because it is inferior to our district's GT curriculum, even after adjusting for the one-year differential. For example, my non-mathy but very bright DD quickly completed the ALEKS 6th grade math the summer after 3rd grade but I didn't consider it as mastery of 6th grade curriculum at that point. Part of your decision will depend on the probability of your DS' return to a brick and mortar school and the curriculum there.
