NHT seems to be a "budget audiophile" speaker. My salesman told me that you have to spend 2-3 times the price of a NHT to get the same quality of sound with other brands.
But this comes at a cost of them being a little "power hungry". They like lots of power to really shine.
One of the magazines uses a set of NHT Super series speakers in their 'budget' home theater room. It is used as a comparison to other speakers where the set runs sub $2,000.