You will mostly get negative opinions around here, but Fred Renzey did recently have this to say in a post:
"As for the Speed Count, I personally think it's gotten a bad rap. It's clearly inferior to traditional full scale counts, but does produce a positive EV. In running what jury-rigged sims I could program for it, it appeared to perform decidedly better than the Ace/10 Front Count, slightly inferior to or equal to KISS I, and considerably weaker than KISS III, KO or Hi/Lo. It simply is what it is, and has its slot -- a recreational player's counting system."