MSD, Pertronics, or AutoMeter???

Im looking into a pair of stand alone rev limiters, and wonder what some of you feel is more reliable and or used friendly, as well as engine safe. I wonder if MSD is more just hype, and also, this autometer brand seems pretty much no BS. But I dont know if its random firing as the other two are. Anyone have any thoughts?

I also see Mallory has a stand alone unit. you can look at the different systems here:
http://www.jegs.com/cgi-bin/ncommerce3/CategoryDisplay?cgmenbr=361&cgrfnbr=159248
if your not familiar with them