I am sure that you will get alot of different answers on this question. I will not give the scientific details like I am sure that others can and most likely will.
Anyways, I have not used SO in any of my vehicles and I have a couple of vehicles with over 150,000 miles on them. I have been a Quaker State boy all my life and I still use it to this day. Regardless of what they say you can go in between oil changes I still change my oil every 3000 miles, plugs every 20,000 and keep up on all the other preventive maintenance. I do not see the need to spend the money on SO when in 3000 miles I am going to drain it anyways. I know what all the manuals say but I am superstitious and will continue to be. If it ain't broke don't fix it.