Are these used players because the NAD players are now the C542 and C521BEE.

I own the C521BEE and it's quite the player for it's asking price of 299. I have also owned the 541i which precedes the the 542 and the difference between the 2 is not huge. A slightly better bass and midrange on the 541i but nothing huge and not worth the 200 difference IMO. Others seem to think the differences are bigger and worth the extra 200.

Hope this helps. In the end just go with what your ear and gut tell you. Not what others say.