One thing I always keep in mind is weight of the saw and your primary use of it. If you can run a bigger saw all day then buy a bigger saw and put a 20” bar on it, you will make easy work of whatever you are doing running the small bar and lots of power with a saw. Brand of saw is all about preferences and those preferences are uniquely yours. Husqvarna, Stihl and Echo are, for the most part, all good saws when talking pro grade models. Since money is not an issue, as you stated, then a 60-70cc pro grade saw would make the most sense to me. I don’t grab big saws (90cc class) unless they are needed and they are not “firewood” saws. They are made for big wood. Smaller saws (50cc) are made for limbing because they are light and nimble and are suited for it.
I agreed with the others that have said dealer support is very important, especially if you don’t work on your saws. Buy what is best supported near you after looking at your options.