DAC purchase:new or used?


Hello. Getting in the digital realm.My budget is 1000 dollars for a DAC. Should I buy new or used? Looking more towards simpler DAC with less bells and whistles, but better components! if that makes sense. My system is very modest.
DAC will be used with Mac Book pro or Sony CDP-707 ESD , Yamaha AS-801 , Focal 836 W. 
Also, could someone explain the "burn in " time factor?
Thanks for taking the time.

rockanroller