[Yetiman]

I am using the Pertronix unit to replace my points, and it has worked flawlessly.
I had an MSD 6AL which failed in the first two weeks, and it was replaced. From the way it acted it seemed like the rev limiter circuitry was faulty. The engine would run but randomly not be able to exceed about 1800 rpm reguardless of what chip was in it.

It was promptly replaced by the shop I bought it from, and the replacement has worked well since.

The MSD unit improved the low RPM drivability, and also seemed to improve fuel economy over the Pertronix unit alone. The rev limiter is far more advanced than the one in the Pertronix unit also. My motor is a small block that is tuned for high rpm power so the low rpm improvement was noticable and welcome.

I have also used a Crane Hi6 which has some diagnostic modes and a retard input (for a nitrous system for example) which also worked very well. IMO, the MSD had a more noticable improvement in low rpm drivability though.