Which is better The magnetic breakerless ignition or the unilite ?
I have a Magnetic setup but There doesn't seem to be a way to test it accurately, and I want to keep a spare on hand, so i'll be buying one of the two anyway. Has anyone had good or bad experiences with either of these. Also I have the 6al w/ rev limiter and mallory 29440 coil, and yes the resistor too 
You won't go wrong with either. I've been running both in various vehicles, in various configurations for years without issues.
Mopar used the magnetic p/u's from 1970-2007 so the dirt cheap boxes at the junkyard can fire the coil. Get one so if the 6 ever dies, you can wire and go.
The unilites can fire the coil directly as long as you have the resistor in line, but they themselves can die. However when driven from a 6 or hyfire, they tend to last a really long time (I'm on 18 years and counting).
Buy the one that is cheapest, prettiest, has sealed bearings, or has the most tuning (curves) capability - whatever your hot button is.