Reliable, takes a beating.  Altho I had the one with the long tubular battery.
  That's the one I have. The long tubular battery was a 1960's lithium, it looked like white toothpaste in a open top tube. I found a brass cap online that allows me to use modern CR123 batteries. 
Love that freaking strobe. Nothing compares today to brightness. Which is weird, the strobes easily 30 years old.