I like Marantz between these two, hands down. I find NAD to be very muddy. Also NAD has a warm signature but at the cost of details. There is too stiff roll off at the highs.
OTH, Marantz is very musical, cleaner and pairs with most entry level speakers out there.
I would go with a Marantz and pair them with some neutral to warm speakers.
You can also go with a Cambridge Audio and pair it with something like Aviano 2.
I would strongly recommend you to take these suggestions with pinch of salt. Go out and take demo of different amps out there.