I have never listend to the amps in question, but I did a little checking myself and it looks like the NAD would be my choice here. I was courious about budget Amps myself. NAD, like many Manufactures of audio gear has produced products that were no better than average to some really good buy's. It looks like the C-316BEE is in the later group.
That said your old Niko is likely no sloutch and might give these two a good run in terms of SQ. You might consider saving a bit more cash for something like Rega's Brio-R or a better NAD which should make a more noticable improvement than the C-316BEE. You've got some Nice gear there, I think it deserves more than Budget Amplification. Just a thought.