E-Tap is a e teaching assistance program. So it's designed to help you teach your student. eTAP gives you K-12 Math, English, Science, and History, as well as SAT/GED/ASVAB test preparation, all on a single easy-to-use website!
Since it's completely on-line you can study anywhere you want to. :) You can use it for your whole family, which means if you have lots of children it's well worth it, but for one child...I can't justify $400. I just can't do it. :)
Most of the reviews are for their highschool curriculum and I didn't really look that over since my son isn't in highschool (nor close to it). They offer a 10 day trial and are easy about extending it if the need is there.