There are tons of video explaining what the Holley system is capable of and how to set up and use it. If you have a basic understanding of computers and know how to tune an engine running a carb then you should be able to figure it out. Basically you're tuning the same parameters but using a computer instead of wrenches and screw drivers.
You can download the software and get a feel for it before you actually buy the system. It's really not that hard to figure out.

 

A buddy of mine has a older Reher Morrison 555 on E85 that we run a single 4500 Sniper on a super Vic. Works great. Best of 9.83@136 in a 3600lb truck on motor with wrong converter. Bolted it on and had it running in no time at all. Tuning is easy once you know where everything is in the program.

 

Imo the systems with the separate terminator Ecu are far superior to the ones with the ecu located in the throttle body. Way less chance for rfi / emi and such.

I’ve only worked on one of the 4500 systems so far. And it worked excellent.

 

Have a 4500 on mine, works great. I/O's are limited though. If you want to run a bunch of sensors through it, might want to look else where though. I do like the SD card in the handheld, pretty slick. I'm getting by the inputs by keeping the Racepak on it, until I upgrade. Can only add 3 inputs on it. No EmI/interference experienced on mine. (Knock on wood).

Good luck, sounds like a fun project!

 

My friends dad has one. Doesn’t know what air-fuel ratio means, tuned itself fairly well.

 

I helped crank one a while back. It went pretty good except the rear blades on both units were opened too far on initial set up. Once we adjusted that it idled down and ran. I do agree that I'm not a fan of the built in ECM. I have seen two that had RFI issues. One is on my friends 60 Biscayne and it will make you want to pull your hair out.

It will run fine until it starts acting up. No ignition wires crossing any Sniper harness wires but it does have a MSD 6al box. I think if you are running a MSD box you need to get it up by the core support on the drivers side away from any other wiring. His is inside the car and I think it's going to have to be relocated.