I had a humphries harness and got very good service out of it. It was a MEFI It worked perfect for many years even survived a car fire. However after about 7 years and 1000's of hard miles little things started happening but very seldom to where it wasn't a big deal. It slowly happened more often to the point I wanted to fix the issue. At that point you are screwed. And there is no direct way to diagnose and pinpoint the issue without throwing hours at it and changing parts and connectors out. This got old. The harness and ecu have a lifespan and can only take so much heat, cold, and violent vibration.
I then went to a danzio harness and life ecu. I have to admit I was apprehensive to deal with danzio because people said they don't answer phone, return calls, etc. unless you were spending big bucks with them. I'm nobody in this sport and race a class 5 car which no one cares about, and in addition I'm on a limited budget. And I can tell you dealing with them was the opposite of what I had previously heard or expected. It was a pleasure, they took the time to point out issues I could potentially have while navigating the install, helped my wiring guy via phone, and id'd future problems I could have, as well as making recommendations for increased reliability along the way and at no time were seemingly trying to push me to go through them. Not only that but It was always effortless to get someone on the phone who could help me. From start to finish Danzio was perfect. And since my car and performance has been top notch.
Also right before I was leaving for the baja 1000 pre run I could not get my car to fire. I tried everything I could think of (which is very little) to figure out the issue. and this was literally the day before I was leaving. Called them on the phone. They answered, and no joke said "hey zac how is it going". I can't remember who I was talking to but he knew right away what to do, I did it and my car was running again. He said if it was a bigger problem we'll remotely attach to the ecu to extract data to trouble shoot it. You can't beat that and I don't think you can beat the service I experienced with Danzio. No I'm not sponsored or paid to say this but I'm happy and will recommend them.
Good luck