I have heard the ref 9 (I believe that is the model) and came away ambivalent. It appears to me that this class of amplifiers - digital switching, class d - or whatever you may choose to call them (though nu-force claims that theirs is better than digital switching) sound good with benign impedence loads - though they have huge power which actually doubles into low impedences. This fact was very evident to me with my Belcanto S-300 amp (I think basically this amp. is similar in design to the nuforce - though each mfr. will claim different/improved technology) which I used to drive the usher be-718 which is a difficult transducer to drive. So despite the fact that I had 300 watts per channel at 4 ohms I felt that the amp. was lacking - and when I switched to the odyssey stratos extreme which I think is actually rated lower into 4 ohms (250 watts I think) the speaker sounded much better. However when I drove my B&W 805 with the belcanto s300 it did a better job. So your experience with these amps. will be based mainly on the type of speaker you are planning to use IMO.
Again these are just my humble observations and not statements of fact.
Cheers
Sid
