My personal experience with the blue regulator was favorable - I ran it for 10 years with no problems. Chrysler did say that it would overheat if was run too long, but I did not experience that problem. The then new Die-Hard lasted all 10 years, although I must say the car seldom ran for more than an hour at a time. Total mileage was about 2500, with trips varying from 1320 ft to 75 miles. With the stock looking solid state regulators now available they're probably a better choice. The blue regulator was "required" if you were using an aftermarket Chrysler electronic ignition package, IIRC it was because the Chrysler ECU wouldn't function below 11 volts and it didn't tolerate voltage fluctuations well.
I met the eBay seller FuryGT that Herb suggested at Carlisle - seemed like a good guy and his parts look top notch, although I have not installed one of his regulators yet. He's been doing this for a while, so he must be doing something right.
I ordered an Airtex/Wells 1V1067 solid state unit from RockAuto last year and while it works well, it has a funky looking short silver cover. I had planned to just put a stock cover on it when I met seller FuryGT (don't remember his name, his business card must be at work). I see that RockAuto now shows the regulator for the Leece-Neville alternator as well.
SC