What are you cutting and how much work? Every day or once in a while? 60cc has a lot more going for it than 50cc, meaning MS362 or the 400. I have the 260 and a 361 - the 260 with a 15" bar on it is like the finger of god, point it at something and it falls over RPM out the ying yang (almost overrevving the thing...). I have 18 and 20" bars for it but seriously, its so good with the 15" I hardly ever put the bigger bars on it. The 361 runs up to 22" quite happily, has enough go to run bigger but oiling is the issue. The 361 is an animal with a sharp chain, it doesn't sound like much being 10cc bigger but the amount of extra go is noticeable and nice when you need it. I've had everything up to 96cc husqy's and 90cc Stihl's - and I don't feel like there's anything around where I am that I couldn't tackle with the 22" bar on the 361. If that won't do it I'm looking at a 40" bar basically, that's big boy toys or borrowing the hydraulic saw off me mate.
I tend to use the 361 for dropping things and anything the 15" bar on the little saw won't get through in one hit - but in every other instance I grab the 260 as it's just so handy and nice to work with. The pro series saws are a lot nicer to operate than what Stihl classes as farmworker or homeowner grades, but they do cost a bit more. It really comes down to do you want a disposable saw if you have a major issue with it, or something that is easily and cheaply rebuildable.
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