Consumer Reports recently published their chainsaw ratings. For a corded electric, their top-rated saw is the Stihl MS 170 C-BQ with a score of 68 points. Their top-rated battery-powered saw is the Ego CS2005 with a score of 84 points. The Ego has a 20" bar. Their Ego CS1804 has an 18" bar and scored 82 points.
Many on this thread recommended a saw by brand name rather than by model. It's dangerous to just buy a particular brand. According to Consumer Report's tests, ratings for the saws from any particular brand varied. Some brands had some saws that were highly rated and others that were lowly rated. For example the ratings for DeWalt saws ranged from a low of 42 and a high of 79. Similarly, saws from Makita ranged from 67 to 74. The lowest rated Ego has a rating of 79. Consumer Reports does not recommend any saw with a rating less than 70. (These are all battery powered.)
A couple of caveats: 1 - You might not agree with Consumer Report's evaluations. That is, for your use, a particular feature should be given more or less weight. 2 - Consumer Reports does not test every saw sold. Just because Ego's saw received the highest rating doesn't mean there might not be another saw -- that wasn't tested -- that would have scored even better than Ego's saw.
Lastly, by pointing out the wide disparity in the ratings of saws from DeWalt, Makita, and others, I'm NOT taking a shot at those brands. Battery-powered tool technology is quickly improving. What may have been a top performer a couple of years ago may be a dog when compared with newer designs. That doesn't mean that the older design might not work very well for you. My point is simply that buying a chain saw based only on the brand might not put the best saw into your hands.
David Walser
Mesa, Arizona