I was in my local Jonsered/Efco/Echo dealer's shop last fall, a fellow had one of those little Mac's in for repairs and was quite dissapointed to learn that it was not repairable in any way.
The guy in the shop had determined that there was a leaking seal causing a lean condition. The store had already signed themselves up as an authorized service center for Mac saws, but was unable to get the right parts. The "official" Mac response was that they would trade whole units, but not repair defective ones. Defective units would be shipped to a service facility, probably offshore, where they may or may not be "repaired" and released to somebody like harbor freight.
It appears that big-box retailers are encouraged to sign up local stores to be service centers for some product, but probably only to inspire customer confidence that problems will be handled. 98% of units sold will likely perform adequately considering that many will see only limited use, and will never require service anyway...after a few years of disuse, they will see the dumpster.
The "Authorized" service guy gets to lose a few bucks stocking air cleaners, gas caps, and spark plugs, but hopefully gets it back when the guy trying to get another use out of his old wally-world special throws the towel and starts eyeing up the better stuff.
To answer the original question: your little Mac will serve you well enough if you keep it clean, sharp and learn safe, effective work habits. It has limits, to be sure, but the most common limit is how long fuel mix can be stored in it and the unit still be expected to perform well.
I am aware of one that has produced about 5 cords of firewood for a retired gentleman...this guy burns up a tank of gas, splits the necessary pieces, loads into a wheelbarrow, then into a trailer behind his car, then home, about 2 days a week, whenever the weather isn't too bad. In his application, the little Mac is possibly as good a buy as any other chain saw. As I opined, the biggest enemy is bad gas, and this saw never sits long enough for the gas to get bad.