Welcome Daniel. That certainly seems like a well thought out comparison of epub download sites - I'm sure people will find it helpful.
Try some of the epub's from this site though - in general (and in my opinion), if it's available here, it's better formatted and nearer to error free. The epub's on this site are usually hand-crafted by people who really care and would not want to release anything that they considered to be sub-standard.
Hope you enjoy the site and it certainly seems like you have a lot to add