I used to run Stihl, but switched to Jonsered many years ago now, and will never go back. Husqvarna owns Jonsered, but if you check out the pro logging forums you will see that the Stihl and Husky saws are regarded about equally, but Jonsered's are usually held in higher esteem and regarded as the best of them for pro work.
There aren't near as many Jonsered deealers around or they'd be just as popular or even more so than the other two. It all comes down to their basic designs and ergonomics because there are only about two places in the world that make the engines, and two or three others that make the carbs, so they all use the same basic parts. It's just how they use them that makes the difference.
Dolmar and Solo both make great saws too.
You just need to try to do some cutting with a few different brands and see what feels best to you. Most dealers will let you run one or two of their demo saws on a log.