As promising as this website looked, I will definitely not be continuing to use it due to the abhorrent waiting time on mastery challenges which cannot be changed.

As I will be majoring in physics and mathematics at university I wanted to review everything from the ground up. Due to the mastery challenge wait time I am entirely unable to use the site to confirm my aptitude for different sections within a sufficient time-frame. I completely understand why it is there, to allow students to review their knowledge at a later date, but actually 'forcing' students to review at a later date thereby preventing them from efficiently moving forward is tantamount to idiocy and completely disregards the learning pace of some students (inevitably creating a rift in their want to continue). A reminder to review areas of weakness would be much more efficient and practical. Or at the very least a setting should be included to choose whether to nullify the wait time or not.

As such, I will no longer be using this website and will find other means. I am perfectly capable of understanding which areas I am weak in and will review them in my own time to make sure I understand the methodology; forcing me to do such for subjects I have no weakness in is ridiculous.

I am incredibly unimpressed by this lack of foresight by the site developers. Until this is fixed I will not be using this website and will most definitely deter others from using it as well due to this critical and unresolved issue.