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.
I've paired nad 320 bee integrated to dynaudio bm5 bookshelf.
They were sounding better with my previous sony vintage integrated amp which i gave away (cant remember the model now 555ES or something like that.)
I have also tried and paired the same speakers with nad 320 as pre out and Marantz mm7025 as power amp. With this i got a substantial difference to the sound signature and highs were crisp though. I beleive dynaudio bm5 needs some powerful amp.
Just by pairing it with nad 320 didnot give me good sound signature. Yes nad is more warm but Marantz poweramp gave it a liftup and crisp clear sound with room filling bass.
IMO, if you are going for nad, choosing speakers like PSB image/synchrony etc. will be the best match. But you should always try mix n match by auditioning the demo.
Recently I purchase BS Focal chorus 706V and integrated amplifier Marantz PM 5004 from ACE Audio Junction it was amazing sound at the store but after install the set into my room sound quality fully difference compare to store the store representative told me give some time to burn the system but as on date I didn't get the effect which i got in store. Now some of my friend advise me change the amplifier and recommend Yamaha A S500.
I am planing to change my step up with Denon amplifier with KEF Q300 which i listen to Pro FX, sound depth is excellent.
Plz suggest me which should i do Replace my amplifier or entire set up?
The condition of the audition room at ACE or at ProFX are almost ideal, but at home it is very different. That is the case with all of us. I am very new at this and have limited knowledge but experienced and knowledgeable members will ask you to experiment with speaker positioning, and perhaps work on the environment a little, also what is the source?