Many years ago, I had the outputs of mine 'upgraded' by Behringermods.com, as they offered to do it free as a trial, as I think they were testing a new pcb. It certainly made a significant difference to the measurements, something like a 20dB reduction in distortion, but made no audible difference. I then bought another (of course unmodified) when the original unit failed. I subsequently found the problem was the internal ribbon cable, so remaking the IDC, it was fine. I've kept the modified unit as a spare, but never needed it.
I can't fault the unit, it does exactly what I need from a crossover, including the limiters which protect my unobtainium tweeters and midrange. I've used the time-alignment function, but domestically, it made b-all difference but it's there, so might as well use it.
I don't use the parametric equaliser as I use an external DEQ2495 to equalise my 'speakers, but I can see it's useful to have.
Overall a great product at a sensible price. It uses the Analog Devices SHARC DSP, (as does the DEQ2496) which is/was used in many top-end mixing desks, and has a huge library of processing algorithms available. This makes development easy, which no doubt helps maintain a low cost for the finished product.