One very important thing to remember here when you're comparing the average iron in one oil to another on here, is the simple fact that each engine is going to have a different level of iron which is normal for it.
So for example, if everyone who runs Mobil 1 on here also just so happens to have an engine which puts out less iron than others, it could skew the results.
The only true way to honestly compare the levels of iron generated in UOA between two different oils is to run both of those oils for a few intervals in the exact same engine. This is why 3MPs testing is going to be so interesting, because we'll get to compare 4 different oils (and possibly 5 if he isn't tired of it by the end of the first 4) in the same engine. It's not a perfectly controlled test since his driving patterns and climate could change, and as his engine ages it might just put out a different amount of wear metals too, but it's going to give us a pretty decent idea of which oils are better, at least for a pushrod V8 engine anyhow. I would love it if more people out there would do a test like his, it would be especially nice to see someone doing it with a turbo 4 cylinder engine, a normally aspirated 4 cylinder engine, and it would be interesting to see someone try this test using conventional oil too.