I have run all three oils that have been discussed. Mobil 1 is certainly not the "most robust" hdeo on the market. In fact its claim to fame has been oxidation resistance, long drain capabilities, but if you want to get down to brass tacks, there are a LOT of oils, synthetic and otherwise, that have "more robust" additive packages. It is certainly a good oil, one of the best, but by no means is it a clearcut winner.
Of the two oils mentioned in the original post, I like both a lot, but I prefer the 9000 Series Schaeffer's. Seems like it holds its TBN longer, and my wear numbers in the same engines appear to be slightly better. Now of course there are a lot of variables in an engines operation that can account for variances in the UOA, but consistently I have been very impressed with the 9000 in a wide range of applications. If you have a source closeby you should be able to buy 9000 for about the same price as Rotella Syn. I buy my Schaeffer's from our esteemed site sponsor here since he live closeby, and it is very reasonable.
I would take 9000 in my diesel apps over any other oil at any price point, I have that much confidence in it. And don't forget to get some SoyShield, Neutra and Penetro while you are at it.
