There are many brands of 2 stroke oil on the market and most are good, some are better.
However the difference between them is mostly anecdotal.
If we forget about straight mineral oil SAE 30 and Castor oil, what is left today are semi-synthetic and full synthetic oils with some variations in the additives that help to mix, stabilize and avoid ash.
Most semy-synthetics are a mixture of mineral and synthetic. The higher the price, the lower the mixture claim, the higher the content of synthetic oil.
Fully synthetic oil like the one used in racing and jet sky engines is the dearest and claims are you can use it at 50:1 and even 100:1
So if there would be a contest as to which oil is the best, it would be a contest among the full synthetic to start with, and the difference would be in the quality of the synthetic base used and the additives.
Yet when such contest may be fun, I must wonder why on earth would I want to use the best possible oil on the planet and then thin it out to the astonishing 100:1.
Am I trying to save money? If so thre are better ways to do that.
As for less pollution, a leaner mixture does not necessarily equate to less pollution. The oil additives used to achieve such low ratio can be nasty stuff and as far as pollution goes, a well tuned carby with the right grade plug good compression and decent fuel will do more for the environment than the difference between 40:1 and 50:1 and even 100:1
As for the 16:1 saw, I have a couple of them and this is what I think.
When the saw was manufactured we used SAE30 mineral oil and the saw would run OK, conceded with some carbon build up and bad plugs galore. Yet the engine is the same, it survived because of the ratio recommended of 16:1. If someone would have switched to 25:1, the then recommended mixture for lawnmower, the saw would have most probably have perished.
Today we have a choice of oil that deliver better lubrication with less carbon build up. So my question is why lean the mixture? If the saw ws designed to burn 16:1 SAE30 how much better will it run with 16:1 Synthetic? Answer a lot better.
Can one lean it to half that? Probably. What about 40:1, may be. 50:1? You can try but again the question is... why?
What is to be achieved with a lower ratio? My 40 Years old Homelite xl12 does not smoke one bit with fully synthetic 16:1 and is still screaming and cutting through bone dry Blackbutt and Jarra like there is no tomorrow. And let me tell you that our hardwood makes your oak feel like pine.
PS
My tip is to add 0.3 fluid Oz of pure acetone to a gallon of mix, and that with any mix and with any oil. The improvement is very noticeable. You can try it in your (petrol) car, 3 ounces to ten gallons. For diesel, 2 ounces to ten gallons.
Use only PURE acetone and keep it away from the paintwork.
I keep a bottle of 2:1 Acetone / Synthetic oil in my diesel 4x4 and put 2 ounces of acetone (plus one ounce of oil) per 10 gallons each time I fill up. The synthetic oil compensates for the lack of lubricity in the modern low sulfure diesel and when mixed with oil the acetone is not so harsh on everything in case of a spill.
I believe now that we know more about lubrication and our oil qualities have improved so much that you never need a mixture that rich. I have never ran an engine on anything richer than 32 to 1 in my lifetime and see no reason to do so, Unless you just love 
