Unfortunately jdownloads plugin breaks functionality with some other plugins like JCE and JCPOPUP :( which stop working. That's the only reason i had to abandon it. I hope author fixes this soon.
If you do not use jcpopup on your website then this dl manger is perfect for you. Sorry had to give 4 stars just because of compatibility problems.
in the meantime we have published a fixed version from the content plugin. ;)