Buy the saw. In a minute. It's a legend. Not available no longer. Plenty of parts and always will be. Power to weight ratio with a 20-25" bar is great.
I have to agree that the MS440 would be a great buy at that price ($340). Consider this: I sold one last year for $500 (PHO) that was rebuilt by a member of this forum. It ran perfectly for a year. Last year a climber took it up in a big tree and then dropped the saw from 40' up. Then the tree section he was cutting fell on top the saw and literally crushed it.
I gambled and replaced all that parts that were ruined, including the tank housing, chain brake, outer handle, all the plastic, etc. I had no idea if it would ever work again, but somehow it had reasonable compression. The case was intact.
Today I started it and it ran well, cutting through 24" diameter maple and noodle cutting the big rounds in half like a champion while pulling a 25" bar. Two thumbs up for the Stihl MS440, another saw that Stihl should never have discontinued.