For most of us non pros only cutting firewood, managing a personal woodlot under 100a, and clearing blowdowns, look at the two pro level saws that will do 90% of all firewood: Stihl MS 261 and the Husky 346 lines. No need for the loggers' big boy saws unless you're logging or doing contract clearing. Or you just like big toys.
Our MS261's with 16" -20" bars and "yellow" semi chisel chains ( the so-called "non safety" chains) do it for us. Less fatigue, enough power to go through all the timber up to 30" which is rare in the N.E. As we get up in years, those 660s and 440s seem to get heavier; better to have a saw that can used safely all day.
A 16" bar with the right techniques and experience will do a +24" DBH tree. Think boring, wedges, planning the fall. Kind of fun.