Reply to DJM 750 or DN-X1600

I'm looking for a 4-channel mixer with a built-in sound card to replace my Xone 62. I'll be using 4 channels of traktor and want an aux input for ableton (i'll be using it with a push) from my laptop sound card. I can get a DJM 750 new for like $900 at PSSL, or I could get a used DN-X1600 for like $650 on ebay. I'll be using Traktor's effects and don't care about the mixer's effects engine. Anybody got any suggestions about which mixer they recommend?