The NX series amplifiers really are worth their price. -Especially ones with DSP.
But first of all, I do recommend everyone to actually seek real measurements of the equipment they are about to buy. These reviews here are merely subjective experiences. For example if you read an amplifier "sounding warm/bright", "revealing more detail" or "lacking bass" etc., that is just bogus. This is simply not what amplifiers do. They just amplify the signal, not alter its tonality. If it does, its either defective, or a tube amp.
There is, however, differences to these pieces of electronics and Behringer certainly delivers good quality at exceptionally low prices.
Power: NX1000(D) outputs ~26 Vrms per channel, or ~52 Vrms bridged.
this corresponds to ~170 Watts per channel (4 ohms) and 680 Watts bridged (4 ohms).
NX3000(D) outputs 49 Vrms per channel, or 98 Vrms bridged. This corresponds to 600 Watts per channel (4 ohms) and 2400 Watts bridged (4ohms).
This really is outstanding performance in this price range. I still want to point out that these are falsely marketed as delivering 2x300 and 2x1500 Watts of power, which they do not. Even briefly.
Signal to distortion is about 81 dB (<0,01%). While this is average performance, it's inaudible, even if you played only pure sine tones.
Signal to noise is 100 dB. This is average within affordable "pro"amps, and actually the NX1000(D)-model produces slightly less audible hiss, than a similarly powered Crown XLS amp. This hiss might be a problem, if you are using big, sensitive speakers near field.
DSP functions are awesome. Crossovers, 8 fully parametric filters per channel and adjustable limiter. Yeah, and Dynamic EQ that might be useful as a compressor for full range speaker or just simple bass boost for lower playback levels, for example. personally I don't use it.
The fan is taking air in from the back of the amp and blowing it trough and exiting front. In my opinion, this is wrong way to do it, but it serves a purpose blowing directly to main amp stage.
The fan IS actually temperature controlled, but it is so poorly implemented that in practice, it's not. the fan whirrs nearly full speed even when cold. And it is noisy! Fan replacement is easy, no need to solder just plug and play, but apparently voids warranty. This is something I am not OK with. In my opinion it's same as voiding warranty for my car, because I changed tires myself. Little provoking example, but you get the point.
All in all, excellent amplifiers for their price!