I fear I am opening a can of worms here but I really would like to know more. I recently switched to synthetic 2 cycle oil because I am a big believer in synthetic oil versus conventional oil being better and giving longer engine life. My big question is does brand really matter. I am using a “store” brand generic synthetic oil. I love Lucas oil products but it is literally twice the price. Does it really matter? When royal purple, Lucas oil, Sthil, husqvarna, and the like cost 50 to 100% more can you justify that quantitatively? What do they have that the generic synthetic 2 cycle oils don’t have? I am not trolling or looking for a fight. Can you really justify the extra cost? And if so what do you base your conclusion on?
There is most certainly a difference in oils out there in terms of the quality. However, when it comes to 2 stroke oils there are additional factors besides just lubrication-there's also deposit formation and how well the oils burn. In theory, you could have a poorly formulated synthetic oil and a well designed blend.
When it comes to four stroke oils I can rarely recall any tests where a generic version performed on par with the best of the name brands. Oil additives and premium base stock adds cost and reducing those levels helps turn additional profit.
Another factor to consider is that two stroke oils are not created equally and that they are typically optimized for one of three applications depending on engine temperatures and various other considerations. Running fancy synthetic boat 2 stroke oil in your saw is a bad idea for example.
1) Boat 2 stroke oil
2) Air cooled power equipment oil
3) Power sports (dirt bikes, motorcycles, 4wheeler)
Additionally, within the category above you should take into account that some oils are blended to perform best at a certain mix ratio. Going overly heavy with an oil formulated to burn best at 50:1 or 100:1 can be a bad idea. For example, I use a synthetic 2 stroke oil in my trail bike that is formulated for a 32:1 mix ratio and it burns off cleanly at that level.
I would advise using a premium 2 stroke oil that is intended for chainsaws and other handheld 2 stroke power equipment and mixing at the appropriate ratio. Knowledgeable people who tear down saws frequently and have large saw shops like Madsens seem to favor Stihl HP Ultra. Echo Red Armor is a newer oil that seems to have favorable feedback from users, but I haven't seen too much testing. Husqvarna HP+ is a blend and not pure synthetic so be aware of that.
Lastly, here's a link to a Youtube video where a gentleman does a nice demonstration of how various 2 stroke oils burn differently by using new cylinders and pistons with each oil:
