I use a pair for 1 year, I use the 99% with the USB port, 2 cl identical USB 8GB each and go (loading 30s), large bags of CDs in the attic!
I struggled at the beginning because there was respect for rules to name the MP3, but greatly pioneer arrang the thing with firmware 1.30.
My usage is intensive, not a single bug! I like the ergonomics, I have no comment ngative formulate, and the effects are top (roll, auto loop 4 times, wow !!! ...) contrary to this ..... DJM600!
I have used in the past but the CDJ1000 USB port ....
I would do this purchase gladly pending future discovery of pioneer!