I've had great luck out of them. Every pyro I've installed on my own trucks and customers hasn't had the first problem, granted this is only about 6 pyros over the past 4 ish years. However the fuel pressure gauges Ive installed or at least the sending units have all failed, most within a two week period all on 98-02's. Which they did replace them under warranty no questions asked, which is impressive when you send 6 back in a month. And up to that time I had only used liquid filled mechanical gauged so I didn't install any isolator of buffer at the time, which may have taken care of the problem.
Anywho, would I buy them again and or recommend them to others, yes without a second thought. Are there better gauges out there that I would rather have yes. Bottom line they are a good economical gauge, IMO the best bang for your buck.