I've been planning to post these for a while. Finally got around to it.
These are the UOA results from my dad's 2010 Outback 3.6. M1 0w40 and 0w30 have been used exclusively for the last 30k miles. Nice low Iron numbers except for the first M1 UOA, which was just after some accident repairs so I suspect lots of really
short trips into and around the body shop. Oil is labeled on an empty line. 0w30/40 indicates a blend of M1 0w30 and 0w40 (I don't have the exact mix, I'll see if my dad kept records). The 3.6R has a ~7qt sump IIRC, and my dad hasn't always been able to get enough of the 0w40. Now that he's done a couple of runs with the 0w30, I think we're going to switch to it exclusively. Seems to hold up well, and is a bunch cheaper than the 0w40 when purchased in the 5qt jug at WM. The one quart of make up oil in the 31,687 mi UOA was totally unnecessary and was Pennzoil HM 5w30. The short trip from the hotel to the gas station (~1 block) caused oil to sit in the heads and the dipstick to read unrealistically low. I'm not sure about the make up oil in the next UOA, I'll have to ask my dad.
His driving is primarily highway, say 80%+. His shortest regular trip is 12 mi to town, and he does lots of trips of 170+ mi from Northern Minnesota to the Twin Cities. He does see absolutely frigid temperatures in the winter though, thus the use of 0w oils.
Nothing to fear from Mobil 1 0w30 in a N/A Subaru, even the new ones with timing chains (which are supposedly harder on oil). Also, Pennzoil Platinum works well.