I don't think it makes as much difference how many hours a year you're going to use your saw, but how many hours at a time you'll be using it. The pro saws will hold up better to continuous use for a long time, but for occasional use the homeowner saws will last a long while too.
I've had the MS362 for a couple years now and I love it, however most of my time with it is spent bucking up big logs, and when I do, it's only for a few weeks in the spring, but I'm at it all day out there cutting...Hence the pro grade saw. If not for the power, I'd have a 261, personally after owning the pro-grade, I wouldn't want to go back...The price stung me for a little while, but it was well worth it IMO in the long run. I burned up a couple homeowner-grade saws before I went the route I'm on now...I guess it just depends on your use and what you're willing to spend, you may be completely satisfied with a homeowner saw. I'm not always a big proponent of 'you get what you pay for' but for me, it holds true with these saws.