I just bought a Ryobi RY40580 last month and mounted it up to my sled. It's a 40V with an 18" bar. Really nice machine.
So far I've used it to make 10-20 cuts a few times out on the trail, in 10 degree temps, and I haven't used more than 25 percent of the battery on one of those days.
I'm really loving the transition from a noisy, stubborn old two-stroker to this electric. No rough, boggy starts and long warm-up times. Quiet and quick.
And, no more carb maintenance.
For trail clearing work, this is plenty of saw. If you want one for actual wood harvesting, you might go with one of the 80V high-end units. They say you can get 200 8" cuts on a single battery with them. This 40V is good for me.