So I hope I'm not sounding like a broken record
but here is what we've found with our very mathy kid (well into algebra at this point, starting algebra II).
ALEX: Okay. Good, not great. The pie charts that they offer for what you need to cover are good, but that's about it. It's generally presented as problem-oriented (solve this problem to see if you're proficient) and not really lesson oriented. For us--and probably you too--the courses do match local curriculum so that's a plus. Costs money.
Alcumus / AoPS : Much, much better. It's still problem-focused in that you're given a problem to solve but there are a couple of things that make it better. First, it's a much better interface IMO. More usable. Second, you rate the question. Third, you
also rate the explanation of the answer. For an auto-didactic, once you get them started they can basically go at their own pace on autopilot. There are nifty "quests" that you go on for fun. Some of them are random and some are focused on solving given problems. DS loves it. Oh, and it's free.
Khan Academy: My new favorite. You may have watched the videos in the past (in fact DS still does on the drive to school) you're probably familiar with Sal. Well they've recently launched a companion web site that coordinates video lessons with test exercises. Best of all worlds IMO. There are also "badges" you can earn for doing various things to keep some of the goal oriented fun. I believe Khan has it broken down to be reasonably close to CA's curriculum. There are A LOT of metrics you can get for your child as well to help you figure out what he/she is getting stuck on. They're actively working on the platform so I expect it to continue to improve. Oh, it's also free.
So our son was doing ALEKs at school but now that he's done with that, he basically just goes back and forth between AoPS and Khan and loves them both.
Not sure if that helps or not, but that's been our experience. We use these as enrichment at home.
Good luck!
JB
