Husqvarna and Stihl are the only saws worth buying if you have serious work to do.
As above choose the brand with the best dealer, both brands are going to do the job.
You’ll need a few extra chains, a spare bar and a selection of other spare bits and bobs along with a means of sharpening. The stihl hand sharpeners that automatically do the rake teeth simultaneously with the cutting teeth are the bomb. If you haven’t got a lot of experience sharpening a chain then I’d highly recommend these. They allow relatively inexperienced people to get a dull chain back to top performance in situ in less time than it takes to take out that dull chain, clean the casing, swap in a new chain and adjust the bar.
You don’t say whether you’re just felling and burning or whether you plan on turning the trees into firewood or timber. If you’re planning on firewood then that’s a lot of work and you’d probably be better off considering a professional saw as opposed to the “landowner” ranges.
I’ve spent a lot of time behind saws and the difference between a pro saw and the others is night and day. Yes it is $300 more (for the same cubic engine capacity) but you get much better power to weight, responsiveness and serviceability. From the very first cut all the way through to the end of a day you really notice it. After a few days work that $300 will be long forgotten. Also, if you sell a pro saw on the second hand market retained value is much better.
If the trees might be suitable for timber then I’d get in touch with a contractor. There are small scale loggers all over the country on the lookout for suitable trees as there’s a national shortage and craftsmen are crying out for usable timber. While you may not make a lot of money, the blokes involved do all the work for you.
Cheers
Ironbark
