Opinions very. Personally, I've been using their products for the past 15 years in all of my vehicles without complaint. I have a 1951 Harry Ferguson tractor that has been needing a crank kit since I purchased it about 10 years ago, due to loose rods. I run a 50/50 mix of SAE 60 oil and Lucas Oil Stabilizer in the pan and on the hottest of days, oil pressure never drops below 20 PSI.
In my 1993 AX-15 ZJ, I added Lucas Oil Stab to both the engine and MT. At current, I have just under 260k miles on the entire original drivetrain, with no oil consumption between changes. I have no reason to believe it won't go another 260k.