The biggest problems I have heard about over the years is the NAD CD players. Skipping, locking up, jams, and other transport issues the biggest complaints.
http://www.audioreview.com/CD,Players/NAD,C540/PRD_117008_1586crx.aspx
http://www.audioreview.com/CD,Players/NAD,C520/PRD_123781_1586crx.aspx
http://www.audioreview.com/CD,Players/NAD,C540/PRD_117008_1586crx.aspx
http://www.audioreview.com/CD,Players/NAD,C520/PRD_123781_1586crx.aspx