i tested the Castrol GPS 20w50 (now called Actevo 4T).
http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9025165&contentId=7046695
had a very high flash - 445 and great susvis of 93.4 in the voa.
also had silicon of 10.
the used oil analysis was a different story.
2.5 hours motor time - flash of 415 with and since 50wt is a 16.3cst or 83.1101 we see that we are out of grade. in a mere 2.5 hours. which was really just 36.89 ground miles in the Sidewinder Enduro.
the *ONLY* castrol oil that i have ever been impressed by and would even consider recommending is NOT a motorcycle oil -> the much flaunted and highly deserving Syntec 0w30 (GC).
oh, so how does it compare?
well, that is a loaded question. to other highly over priced non-performing motorcycle oils: it's on target.
against a highly over priced, quality product (ie maxima or motul) then it is quite lacking.
against a good priced, quality product (ie Super Tech 15w40, SRT 15w40, delo 400 15w40, delvac 1300 15w40...........) then you might just as well take your wallet, throw it in the toilet. stick your head in to look for it and then flush.