Advice Please...H/K or NAD?

My first post here...I need some advice. Within the past year I purchased a Harman Kardon 3490 2 channel receiver. I am done with home theatre, and this H/K piece seemed to be reviewed very well in all forums. I have been using it with a pair of Klipsch KG 4.2 speakers and have been pleased with the set up. That was until I came upon a used NAD 2400 THX amp and a 1600 tuner/preamp, which sounds awesome as well, and I am at a stalemate. I know, the best advice is keep 'em both! But that is not an option, so which set up would you keep and why? Thanks!