Originally Posted By: 92saturnsl2
If one believes what's written on the bottle, Mobil 1 Extended Performance would appear to be a no-brainer... (guaranteed ~15k interval, exact number eludes me at the moment).
Yes, M1 guarantees EP for 15,000 miles (for whatever that is worth), unless you drive in harsh conditions (stop and go, excessive idling, towing, dusty, etc). Same guarantee as Edge. Price for Mobil 1 Extended Performance is $28.50 for 5-quart jug at most Walmarts ($26.00 for regular M1). $34.00 for Edge.
In Castrol ads, they say Edge is "unsurpassed" by Mobil 1 Extended Performance in terms of wear protection. Translated, that means that they are about the same (according to Castrol) and they are not willing to say that Edge is better than Mobil 1 Extended Performance (but they do claim it is better than regular M1).
Interestingly, they do specifically claim that Edge has some PAO base oils (among other base oils), which is something that Castrol Syntec does not claim (neither does PP to best of my knowledge).
http://www.castroledgeusa.com/#/faq