Never had my hands on one but I did talk to a client that owned one of the Classic Recreations cars with this on it and he said the car ran great.
I dealt with EEC IV MAF systems quite a bit back in the day and it is true that they do have "limitations" when dealing with more extreme engine combos. But like anything in this industry the term "bolt on" is a misnomer. The educated builder is going to learn the product he is installing and have the wherewithal to make adjustments for the outside of the box applications that are part of our industry. With the EEC IV MAF systems once you got any more into an engine than a set of motorsport heads, cobra intake and an E cam you were upgrading injectors and having the MAF remapped to match. The more air you stuffed in, the bigger the injectors, the bigger the MAF to match. As mentioned the 5.0's ran on a Hall effect (Dual sync) distributor to provide cam and crank signal for SEFI operation and they were a great running vehicle as long as you knew what you could do and what you had to adjust for.
Like many here I've dealt with A LOT of cars with high end programmable EFI systems from "professional" shops that ran like crap. Like many of you, I constantly get asked "Who's system is the best?" I've dealt with FAST stuff for the last several years and know them well so I use them... I've had bad experiences with other systems that ate my lunch. What it really comes down to is that if you are paying for a quality system and have a quality install it comes down to the fact that you also need a quality tuner to set it up for you. If you have a guy that is awsome at ACCEL systems- by all means go for it; Your tuner is a FAST baddass- Rock it. It's all about what you know and how you can make it run to meet your clients needs; and being there to service it as needed.
I am really excited about the "self-tuning" systems because I have a lot of clients who really don't need a fully programmable EFI system for their "daily driver"- and call me selfish that when I send a vehicle back home several thousand miles away after upgrading an EFI system I cherish the thought of not getting a phone call because this car I set up in 85* ambient all of a sudden is being driven during a 55* cold snap and hiccuped... once.
But hey... that's part of living the life right?