This is a super-useful thread--thanks for assembling, Carcass!
Is GRE Prep Club going to add explanations to the questions from the 2 new paid PowerPrep Plus Online tests as well? I would be happy to contribute to that project.
If you would prefer a professionally printed guide to the PowerPrep tests that I co-authored, with detailed explanations to all 320 questions, then go
here.
The download link to the old PowerPrep software is helpful, too--since the PowerPrep Online tests aren't always functional. I have the old Mac versions of the software, if anyone is interested.
-Brian