I don't know why Redline is the 'red headed stepchild' on the forum.
Redline is a great company and they make some of the best products I know of.
I also use GC 0W-30, Mobil 1 0W-20, Delo 400, and Delvac 1. But if Redline made a 0W-20,0W-30,0W-40 I'd use it. And I haven't tried Redline's 15W-40 since I've had good luck with Delo 400 and Delvac 1.
Were people trying to convince themselves they didn't need better oil at $7.00 /qt?
Now that Mobil 1 is $5.68 / qt at Wally World... Redline does not seem expensive.
But even when Mobil 1 was less than $4.00 /qt on sale...the Redline products have always been worth the money.
I've used Redline for 10 years, and the engines, gearboxes, differentials, injectors in all are cars that run Redline are in fantastic shape...despite frequently driving the cars as hard as possible, or close to it, for much of their life.
I use Redline 5W-30, 5W-40, 10W-40, MTL, MT-90, 75W-90, 75WS-90NS, SI-1,Diesel Fuel Catalyst, and I used to use Water Wetter.
I plan to use Redline 5W-20 in our Honda VTEC, and I may try the D4 ATF in our BMW automatic.
Plenty of enthusiasts and specialty shops use Redline for modified cars, or cars that see some track use, and I can see why:
No synchro problems, no engine wear, great UOA's at 10K intervals.
Redline is a great product, and Polyol Ester is a great basestock, IMHO.
I have little first hand experience with Motul, other than their high temp brake fluid.
But I would expect great things from Motul oils and premium ester basestocks.
I also expect great results from Specialty Formulations products. I hope to try their gear lubes soon.
I did see the sludge in the reservoir from Water Wetter when mixed with Dex-Cool/ distilled water. I stopped using Dex Cool and switched to G-05/distilled water, and I haven't tried Water Wetter again. If Water Wetter is a surfactant it may be as simple as cleaning junk off the surfaces.
Dex Cool on the other hand is junk, IMHO. I regret using Dex Cool. It is just too sensitive, and appears to react to contact with air.
Now I stick with the factory coolant, or Zerex G-05.