Our DS8 is using Aleks. I don't have any experience with Singapore, so unfortunately I can't help with that.
Aleks is working well for us. We homeschool, had been using Teaching Textbooks' Algebra I until recently. I found some parts of TT that didn't work for us, and found Aleks when I was looking for a similar (computer-based) math program. Aleks does a lot of what TT did, and quite a bit more. It also addressed specific concerns I had about mastery of certain concepts that our son was having trouble with; in TT, he didn't get much of a chance to work on those before moving on, whereas in Aleks, he *must* master them before moving on, even if that means having to do 20 similar problems.
Also, I like that I can print worksheets and schedule assessements (tests) whenever I want. We live in a state that requires a lot of paperwork from homeschoolers, so it's also nice that Aleks has that end of things covered, right down to mapping what DS can do against our state's math standards. For our son, the whole pie thing is very motivating. One more plus is that Aleks does an initial assessment that is fairly in-depth, so before you even start you get an idea of exactly what concepts your child knows and doesn't know.
Tara
