I use Aleks a lot due to my math teacher assigning 10 topics a week, unless it is a shorter week, which in that case he assigns 5 topics. I think it is a great program that allows kids like me to learn at their own pace.
If you are new to a topic, it will give you an example of how to do it. If you get a question wrong, it will give you one more chance to solve it correctly, and then it will show you the answer along with and explanation.
The problems I have with it are:
1. The constant knowledge checks
It gives me a knowledge check every other week. This can become frustrating as they can take hours to complete. It also tells me that I have mastered a topic, and then one week later I am again reviewing it again.
2. The site kicking me off
Aleks basically kicks me off after a certain amount of time of me not doing anything on it. Sometimes I'll keep the tab open as a reminder that I need to get it done, and then when I finally am motivated to do it, it will make me go through the process of signing in again.
3. The examples
Lots of times the examples Aleks gives me are helpful, but there are times when they aren't. Sometimes I need to get extra help from my parents, who aren't able to help me until nighttime when I'm supposed to be doing other things. There isn't much Aleks can do about this issue, but it would be helpful if someone did something.
Sorry about the credibility level; there's not much I can do because I'm still a kid.