Yes, I used an MPX 820 for many years. Working mainly as a solo performer, using a foot switch, it allowed me to do fade outs, add delay to single words, and other interesting mix changes.
I modified it to have balanced outputs on the Left Right Main, and Monitor outputs. I also added switchable Phantom power to the microphone Inputs. This mixer used a programmable 6 pin IC called the Xeta. Each individual IC had differing characteristics, so to balance the different functions on each Channel, each chip had to be measured and calibrated to be matching across all 8 Channels. The chip was hard to get from Akai as a separate part, so I ended up buying two extra MPX 820's so I had enough chips to choose from.
As my needs changed, I moved on to another mixer which had more Channels and Aux sends. But I really loved the MPX 820, and although I don't use it for the moment, I could never bring myself to sell it, and will keep it forever.