If cost is the only benefit then I will spend the extra money to not be rebuilding saws. My saws don't smoke at 40:1 new or old. Buy a flat blade screw driver and tune them. I bought my last thing of echo oil and 2 gallons of ethanol free gas last year. Still have 2 thirds of the oil and I need to buy gas. I cut a lot of wood on a container of oil. If cost is an issue buy an electric saw. Oil is good.
My experience:
Recently I was in Walmart and noticed premix for around 20 bucks a gallon.
At the rate I use petrol it would be insane for me to pay that much.
Once I bought NON ethanol petrol. Paid more for it. Mixed it properly, lost a string trimmer and a blower. Terrible stuff.
Most equipment calls for 89 or above octane. Newer equipment (most times) has been upgraded to endure some alcohol.
During cold weather I mix Midgrade at 40:1. In hot weather I use around 92 octane because it burns cooler.
Every piece of equipment that I have is holding up well with 40:1 and having a single mix makes life easier.
A big mistake is often in mixing. A gallon of gas is 128 ounces if we add 2.6 ounces to 128 ounces we've increased volume by 2.6 ounces. That is not a proper 50:1.
I measure 128 ounces in a container with clear marking. Then I pour about 5 of those ounces in another clean container.
Next I add 3.2 ounces of oil and 1 ounce of Seafoam. I cap the mixed gas and shake well. Sit on a level shelf and wait for it to settle. It will then measure near the gallon mark, usually just a tad less.
Next I slowly add the fuel I previously removed from that gallon before anything was added. When that mixed fuel reaches exactly 1 gallon there will be 128 ounces of fuel. In that mix there will be 3.2 (40:1 mix) ounces of oil and 1 ounce of Seafoam.
The Seafoam will stabilize that gas for a full year. It will NOT alter the Octane.
If I leave fuel in a seldom used saw, a year later I'll top off with fresh fuel and start the engine. My brother used Premix 50:1 from his Sthil dealer. Now, about a year of storage his seldom used Echo 600p won't start.
This is my opinion. Others vary but I'll mix mine like this until I die.
When I bought my 4 cycle Generator, I ran it without a load on a quart of my mixed fuel for break in. An old Mechanic taught me that trick. For his 4 cycle tools he always used some 2 cycle oil. Older 4 cycle engines used 4 ounces oil to 5 gallons of fuel. His opinion was all petrol came from oil and when refined to much oil is removed so he thought we need add a little back. However, only during break in or when I need to get rid of old 2 cycle fuel does mixed gas go into my riding mowers or generators. But Seafoam is used quite regularly. I was told - may not be true- that Seafoam actually helps stop the alcohol from damaging the rubber gas lines etc.