The way I see the scenario is,
Langdon: It gives you HEI and the ability to get off the shelf parts at any FLAPS, it doesn't look anywhere close to the original but will function good.

Mallory: If a person is doing performance upgrades using modern parts it is probably the go to unit use.

Pertronix: This will allow an upgrade to electronic ignition but still retain the look of an original distributor. Many guys have had issues, but many have also had years of success.

Jason: This is a 100% do it yourself conversion and will take time to do and get working. If you are hands on and want to say you did it this is for you.

I don't think mileage will differ much if a person were to do a test on the same engine using all 4 different options. As to the performance side of things I think that the more other things have been done to the engine it will benefit more with different distributor options that are more suited to the application and intended use.

Don