As a former dealer for Echo, my first question to anyone that came to my shop looking for a chainsaws is: What will you be using it for? Stihl used to be an excellent brand, but the last several years, their consumer level models such as the MS250 have gone downhill fast, and these days are not much better than what you might buy at wal-mart.. the last few I had in the shop for repair before closing the shop, looking real close, I regularly noticed the words "Made in China" on may lower end (I.E. cheapest model they could get in the bar size they wanted) Stihl models , and the construction and quality of those really showed through.. If you were to get an older "REAL" Stihl before they started the MS- labels (Such as an 025 or 026 which should be relatively comparable to the MS-250) then I'd be less hesitant to recommend them.. but those are hard to come by any more... Similarly with the low end Husqvarna models (Husqvarna bought Poulan-Weedeater, and most of their consumer models were nothing more than an orange colored Poulan you can buy for less at Home Depot) Echo is still made in USA (though Japanese owned) last I knew of, and decent (Such as Timberwolf) firewood saws.. Even their smallest model (at the time I sold them) the CS-210 with a 14 inch bar was more than enough for a lot of my customers that just cut smaller poles for campfire wood...and they sold for $199 - less than a used MS-250.. and around here, there is absolutely NO WAY I would ever pay $250.00 for ANY used chainsaw unless it was one of the professional models and I was allowed to give it a good run through its paces - I'd sooner buy new (In fact I am considering one of those chinese 52cc models with 20 inch bar on Amazon.. I'd be getting roughly the same quality as any of the box-store saws, but for a LOT less.. only caveat with those is, there's no where really to get warranty... I wouldnt even worry about parts availability - by the time you had a dealer put in a carburetor rebuild kit, and give it a good tune-up, chances are you'd have spent another $250 just in repairs... (which is usually why these are up for sale - they need work that'd cost more than replacing the saw)
In a nutshell, if you wanna spend $250 on a chainsaw, whatever you do don't let the brand name dazzle you... Consider what it might cost to fix them up (some saws, only place you can get repair parts such as carburetor is from the O.E.M. Dealer, and in some cases, new carburetor cost almost 3/4 the price of a whole new chainsaw... I'd recommend (highly) foregoing the used saw market (unless they're running, fully working, not stolen, and under $100) and just buy a new one - at the $250 price point, brand isn't really gonna matter... there'll be little if any difference in quality... (Though, if you go to an Echo dealer with a good reputation, their 5 year consumer warranty is solid - I've twice replaced the broken saw with a whole new unit under warranty from Echo, as a dealership for them, so I know the factory DOES back up their warranty.. though some dealers have been known to arbitrarily just say it isn't covered by warranty (because they rather just sell you a new one)
But in a nutshell, the first thing before offering suggestions would be to determine just what you want to use the saw for, what you expect to accomplish with it, what size bar do you really need (I use a 40v Wen cordless with 16 inch bar, and it works beautifully for the most part, though processing big logs for bowl blanks, I can only manage 1 or maybe one and a half 20 inch logs before needing to recharge for a couple hours) and how much you really use the saw in any given session...