struggling to get extension added to my devices and browsers; based on what I'm told by active users this is really effective.

Don't jump directly based on its rating. Instead use the additional details it provides to form an opinion. It highlights what various news outlets do well and what they don't.

This doesn't seem left or right leaning but it will definitely annoy those that are blindly left or right leaning.

I'd give it 5 stars if had details on more news outlets and I'm referring to major international publishers that have not been rated yet.

This extension gets four stars, for now.
Most of this accolade is for the idea and some of it is an encouragement to further development into a truly impartial algorithmic guide (insofar as this is possible).
I think the red-and-green categorisations are a little too black-and-white and likely to be controversial (because, increasingly, almost nobody among the general population reads "the news" without some acquired bias). Perhaps *White* should mean "so far as can be detected this site is trying to get it right" and *Amber* should mean "there is some doubt about the veracity of some items on this site" with, in both cases, a link to more detail. A third colour (Blue?) would be useful to indicate news aggregators with a legend along the lines of "This is a news aggregation site. Please check source articles on the originating sites".
Finally, it is disappointing that a particular print-and-online "news" publication recently had it's rating changed from "Red" to "Green" without changing its editorial stance in any way. To my mind "Red" was thoroughly deserved because the publication presents opinion as if it were fact and habitually spins news to such a degree that it winds up seeming to mean the opposite of the original facts. Others will disagree with me on that assessment but independently verifiable "facts" are "the news" which the reader should interpret whereas "opinion" is someone else's (often malicious and politically motivated) interpretation. When opinion is dressed up as the news it is *fake news*; when a fact is twisted it becomes a lie. If, under the colour scheme suggested above, the publication in question were to be marked "amber" (with straight-forward explanation) - No Red, No Green, - NewsGuard's rating would be less likely to seem biased, even to some of the One-Star Generals who, in this comment space, have denigrated this nascent attempt to differentiate information from disinformation.

Fairly accurate rating for most sites. I personally disagree with some of the detailed assessments but the Green / Red assignments are pretty spot on. No news source is perfect but this extension easily identifies a news organization versus a tabloid infotainment site.

Extension gives a rating that is fairly permissive depending on a number of criteria, but *not* whether it's left/right bias (a lot the the 'reviews' have not understood this) and clicking through will give you a detailed explanation for that rating. If you have a relative if gets their news from palmer report, american thinker, swivel-eyed loons on youtube or similar then this extension may well be helpful for them.

On the downside, there's no options to make the extensions less intrusive.

While this is a must-have addon, it is as well to remember that no amount of automation can replace rational thinking and common sense, so if you add that you should be fine.
And take warning of many of these reviews - clearly many people have their own biases and this kind of add-on directly harms the credibility of their own ideologies, and an addon such as this only reveals the deficiencies of their favoured propaganda outlets.