We suggest buy the one that comes in a bottle colour your wife/kids/neighbour likes, so long as it is a suitable grade aviation oil.
Jaba,
The two areas in the aviation field where oil characteristics may be different have nothing to do with pretty bottles (or in my case, until recently, 220lt drums) or with viscosity, but are "anti-corrosion additives" and the ability for a film of oil to "stick" to surfaces.
If you have a flat engine with the camshaft above the crankshaft, this will be more significant, re. the "sticking" means the camshaft will still have a measure of surface lubrication until the oil is flowing after start. I am certain we know all the trials and tribulations of Lycoming camshafts and followers.
IN times gone by, a good mate of mine did all the cam regrinds and repairs for several engine overhaulers in the Sydney area ( and many from further afield) and it was rare to see an auto camshaft as badly worn as the "average" Lycoming --- a bump stick with little of the bumps left.
Modern auto oils are, from what I can see, far superior to available aviation oils (even if your engine is "approved" for the few available multi-grades), I guess a matter of market size and demand. We still have plenty of engines around aviation that are not even "theoretically" approved for ash-less dispersant oils.
Further, it still seem to make a difference with aviation oils whether they are a paraffin or olefine base, something that has long since ceased to be an issue with auto oils.
Interestingly, in US, many operators of round engines swear by one of several well known automotive additives, in the hard life of ag. engines, consistently being able to achieve recommended TBO +50% helps keep the cost down.
I better not mention it here, I wouldn't want to encourage criminal behavior amongst those in Australia already committing aviation.
Tootle pip!!