My own feeling on any of the 50cc saws I've run, is that without special consideration and a little babying you could probably burn any of them up fairly quickly with steady use. You can correct me if I'm wrong on that, and I admit this is probably because I've mostly run 365's and 372's. They are overkill for much of what I do but they never feel like they are struggling. In my particular application you don't need to worry about what bar/ chain you run, you don't need to worry about the finer points of filing and raker height, and you don't often need to worry about pushing them too hard. By comparison the 50's often feel like I have them running on the edge of their capabilities, but maybe that's just me.