450 is a very nice saw. It will be spoken of highly here as more guys start running them. Very smooth. 445 is slightly smaller displacement wise. The 435 is built on a smaller chassis, and you notice that it's a bit lighter than the other two. It is actually around 40cc, so it's a pretty snappy little item. The OP really didn't say what kind of cutting he is doing, so we really don't know how much saw he really needs. I honestly don't have enough real world experience with the Stihls mentioned, except maybe the 026 to give any insite as to how they compare.
The carb issue on the 359's does seem to be confined to the more recent saws. But, I don't think it's simply a bad batch, or Husky would not have switched. I was told that there was a problem that Walbro was unable to fix. I'd have to look it up, but I suspect there was a change/update to the carb for emission purposes that may have introduced the problem.
As for the "pro" type of saw for a guy doing his own firewood cutting, I don't necessarily agree that the average user really benefits all that much from the extra money spent. Nicer, definitely, but not always necessary. If you're doing 10+ cords a year in an OWB, and cutting lot's of big stuff, then yes you are better off with not only a pro saw, but a saw that's larger in displacement than any homeowner models that are available. But a guy that's doing 3 to 5 cords of wood and rarely cutting anything bigger than 12" will do fine with a good Husky or Stihl homeowner unit. Both brands have a lot of overlapping models of pro and homeowner saws in the 50cc to 60cc range. Here on the site we are all enthusiasts, so we lean towards the nicer units. But in the real world, Joe Woodcutter is buying 450's, 455's, 460's, 270's, 290's, 390's, etc. They are cutting TONS of wood with these things. The saws are reliable and hold up well. They come in for service with the same problems as their pro counterparts. Fuel issues, filters, cleaning and maintenance, occasional busted mount or bent handle, stripped oil gear, etc. Just the usual stuff. But we simply do not see any additional problems or failures because they are not "pro" saws.
I also think that too many guys get hung up on the plastic crankcase thing like it's some kind of great barrier between pro and non pro. The truth is that there are very very few problems with these saws due to the plastic crankcase. The only thing I've seen is on some 350's with the muffler coming loose and exhaust gases melting the case. But that was a muffler issue, not a crankcase problem.
Power wise, a pro saw will be somewhat quicker that a homeowner saw of the same size, and most of us guys here love that extra snap. But again, for the average guy that's just cutting up a pickup load of wood, it's not very important.
muffler mod.
