I have two ViparSpectra 165s over my 40 breeder and have to be very careful. They're running 40% on both channels and I've fried a few acro frags with them. Pretty sure these things could literally give me a sunburn.
No complaints about them either. The color looks best to me with blue and "other" channels the same intensity. They also seem to look better at higher intensity. Like others have said, my skimmer is FAR louder than all 4 fans running. The built in timer was also a must have for me.