Was there a personal all time best?

[addyguy]

Petro-Canada SM-spec 5W-30 Supreme conventional in my 2002 Cavalier.

It ran noticeable smoother, used a lot less oil, and started up easier in the cold with this oil compared to many others - ST, PYB, GTX...

 

[pitzel]

Esso XD-3 0W-30 CI-4 rated. It had a very high TBN, and I've personally run it on >40k mile drains without any evidence of sludging in cars.

I still have a bit stockpiled from over 10 years ago, but the new stuff (Mobil Delvac 222 0W-30) isn't quite as good I am told in the TBN department because they toned down the ZDDP.