I used to have a DNM 6A pre & Gem power, later pairing the 6A with modified EAR 519 monos. Also had a Linn pre. Never any Naim gear.
To my ears, DNM sounded DIFFERENT than the Linn. The DNM pre was very analytical and clear; it also suffered heavily (& annoyingly) from RF. As to superior... for me, yes -- but that's clearly subjective.
What kind of music, partnering equip is involved? Also, which DNM / Linn / Naim product(s) are you considering?
More info would help. Regards.