At the time we bought one for my dad's car, it was before the internet was big, and they were one of the only people advertising a 19 spline converter for the early 727s. Anyways my dad's 3000 stall has been working fine since day 1.

If I were in the OP's shoes, I'd only run it if it was known to work, and if you don't have plans to sell the car since it will not be a selling point. Yes, anyone on the internet can say that it's certain to grenade and take your car out with it. But most of what you see bashing GER, deserved or not, is not from direct experience, just a reputation. Since bad news and rumor travel faster than good/no news, the quality of converters may be better than their reputation.

Keep in mind they sold a ton of converters, huge ads in all the magazines in the 90s, so there are probably many of them out there working fine that no one ever hears about. In this thread, there are people with good results and people who have not benefitted by switching to a higher priced converter with a better reputation.