I haven't tried it, but I have yet to hear anyone say anything bad about it, and I've looked! We're using Singapore and like it, but we hit a rough patch and I looked at other options. Aleks was tops on my list.
The only drawback for me was that we'd have to be home and online for DS6 to do his math. Since we usually have school at my 2nd son's preschool to save on driving time, that wasn't the best arrangement for us. But if Singapore stopped working for us, Aleks is probably what we'd use.
I don't know if that helps, but it's what little I know.
