In the live sound world, they became a loathed product. More or less, only a tool would be caught dead with it in their PA system. They found a resurgence several years ago as a recording tool, but again I think they have gone by the wayside in that market. They have always had some support from guitarists using them in their FX loop, which I think is what drove their pedal product line. Now, again with the pedal craze being more about " boutique " overdrives and fuzz 's, subtle effects like BBE's Sonic Maximizer is just not topping any love charts.
The effect is pretty much a gimmick anyway. It supposedly " aligns " the lows mids and highs so they come out in the right order..... Perhaps 20-30 years ago there could be an argument for it when most PA systems were badly aligned in the time domain. It could give at least some semblance of " time alignment ". It is more that the " time " aspect of their design is the marketing point. The quick and dirty of it is that it is an active shelving crossover. The highs come out first because they aren't pushed back in time by the filter networks. When you turn up the " process " you are turning up a 10khz shelving filter, the lo-contour control turns up frequencies below about 50hz. It is the equivalent of a Fletcher Munsen processor for loud audio systems.
For guitarists, it could be seen as a mid-scoop sort of tool. You get the highest of highs, and lowest of lows that a typical guitar speaker cannot reproduce naturally, giving the effect of clarity and power. That is not a bad thing per-se, but.... if you look at from a technical standpoint it can be. The phase shift that occurs from that effect out of a single speaker will be seen as phase shifts. These phase shifts are measurable and can be an issue, just as much as they can be a blessing. I had on in my rig 20 years ago too, then I started doing sound, and learned real quick that I was wasting energy on trying to make it work for me in a productive way. It just didn't work. It was an effect, no more, no less.