I’ve not heard a genuine NHB108 however I have heard the 250WPC KR Audio Black Widdow NHB108 clone. My Absolute Audio Labs SIT-A15 power amp is ahead though only when paired with its matching ASL-1Z preamp. The NHB108 copy sounds better with a larger variety of preamps and has the sonic attributes written about in various reviews of the genuine NHB108 which is frankly absolutely magical.
That said my Absolute Audio Labs gear is the perfect match for lovers of high efficiency full range drivers. These fall apart driven by the 250WPC NHB108 copy yet are magical when paired with the 15WPC Tokin VFET circlotron amp. The NHB108 copy on the other hand seems to perform magically with multi driver speakers and I’ve not noted any limitations when it comes to bass. In fact it’s the best sounding bass I’ve heard.
That said, for me I love full range drivers so have some 1.75m behemoths being built for a new pair of 103.3db sensitive Lii Song Platinum-10 drivers I’ve sourced. Massive cabs needed to get a fairly flat response to 30Hz. ;)