I have mentioned this stuff a few times, but this Stihl HP Ultra two-stroke oil is well worth its premium price.
I started using this stuff after it was thrown in on the sale of a new machine a few years ago. At the time, I couldn't see why you would bother with a synthetic two-stroke oil, in both price and being locked into buying from the one place. But this stuff runs so clean it saves me time cleaning out exhaust screens. It smells a bit funky once burned though, not the usual two-stroke smell.