What EFI setup are you running?
The FAST system we bought was not.
That's the thing. I'm not familiar with Edelbrock, but the Holley system is VERY adaptable. If you don't mind chopping up the harness, (and you can buy an unterminated one) it is VERY adaptable.
I do have some minor complaints about Holley, but some are "workable."
The O2 sensor is proprietary, which I personally think is B.S. They claim they are "individually calibrated." Not sure I believe that
The Optional (separate) O2 display gauge.........Holley did not put the wiring in the harness, and is supposed to send the extra wire with the gauge. This means not only must you tear into the harness and connector, but that you cannot adapt a brand X gauge. It might just be--and I intend to find out--that the Innovate gauge I have is the same output range!!
Holley does not supply all documentation in "easily handled" form, I printed or at least pdf. Some of the docs (help files) are built into the software. Now I'm a "printed paper" kinda guy. But a little Google showed me that I could extract the help file and print it out. This turned out to be a big help (for me)
I've heard bitching that the Holley system has no native support for the late hemis. Really all this means is, you have to round up the proper hardware and wire it yourself.......there is no native "plug and play" harness to interface the holley EFI with the Mopar harness / sensors.
And, the ECU is not repairable, it's potted. At the cost of these, not sure I'm too happy with that. There was one guy over at the Holley forums who'd messed up the USB connector. Not a good deal.
I had "buyer's remorse" for a short time after buying mine, but have since warmed up. I've seen some "good" comments about how quickly the Holley system can correct itself.
I STILL KEEP Megasquirt in the back of my mind. If I get "time and money" I'm still thinking of picking one up to play with.
