My dad has had a Stihl MS-280 with an 18" bar for YEARS. Up until about 2 years ago, He'd have a guy drop him off 8' pieces of wood so I could cut/split/stack it. He used to burn about 20 f/c per year at his shop.
In tandem, I'd also use a little 12" Redmax saw if I had to cut a lot of smaller wood.
We've had zero issues with either saw. I've probably cut at least 1000 f/c worth of wood in my time, all with these two saws. Neither of them have gotten anything more than a tune up, a bar replacement or two, and chains. We store them all winter and sometimes don't even empty the gas out of them.
I didn't read through this entire thread, but my biggest recommendation to you is to learn good saw practices. Don't use extra force on the saw to cut wood. If you can't just lay the saw on the wood and have the saw's weight do the cutting, then it's time to sharpen or replace the chain. That "stupid" advice that my grandpa instilled on me at a young age has given me the knowledge to be able to cut quite a bit of wood before I even need to think about changing the chain.
Also, if you respect chainsaws (like EVERYBODY should) and are comfortable with your ability to use them, you can get a rapid super chain. These chains are PHENOMENAL when it comes to making quick cuts with minimal effort.
To me, like many other things, buying a chainsaw is a "buy once, cry once" event. You'll probably pay more for a good, reliable saw at first, but you'll save in the long run by not constantly having to work on it or pay somebody to work on it.
I can't even keep track on how many trees this thing has fell, limbed, and bucked over the years. This is bar #2 in the pic and needs another one now. Not sure how many chains and sprockets I've gone through. I cut pine, poplar, maple, oak, beech, and cherry the most. Diameters from 6" to 24" most often.