The best saw is one with a sharp chain. They will all do the same thing, some faster by a few seconds, if that. I personally like the Stihl, comfort wise.
If you only cutting firewood with logs 12in across and smaller you can get a Stihl 026 or MS260 MS261 AND IT WILL DO THE JOB. If your cutting 20" and bigger logs sthil 044 046 MS440 ms441 MS460, Whatever you do, dont get the Farmboss ms290 ms291. I like to have at least 2 saws, a smaller saw for the smaller stuff, lighter weight, and a mid/larger saw for the big stuff. If you never used a Chainsaw, start with the smaller saw, and work your way up. My all time favorite would be Stihl 044, it will crush those farmboss saws ms290. Hope this helps.