Echo and Stihl are both good brands. So is Husqvarna, which I have.
Don't go overboard on bar length. My Husky only has a 16" bar but I was able to cut down a storm-damaged pecan tree that measured ~108" in diameter.
Some of the lesser known brands have good reputations, too, such as Johnserud and Dolmar.
I also have an early '80s Poulan Micro XXV which is still going strong but I can't vouch for today's Poulans.