These are very neutral sounding amps. They will work as they come, but are not really finished, for universal operation you should add an input buffer.
If you ignore this fact, the resulting sound depends very much on the pre-amp you use. While they will sound great with a strong, active driver / buffer, a passive pre is the worst you can do to them.
This explains the different impressions and opinions about them. You find ICE modules in some very expensive high end amps, as well as in active loudspeakers, monitors and PA.
So it depends on the way you implement them into your system what you will get. The 50ASX2 got some negative critic they do not deserve, as they often fail if used in bridged configuration with too low load resistance. TEAC sold an amp based on them too, this was know to cause all kinds of problems, which where not the fault of the ICE modules. Just a very bad implementation by Teac.
While the 50/125SX2 should be driven single ended, there are the amps of the 250/500/1000 line, that have to be driven symmetrically to give best performance.
