I would say comparing GoAccess and counter.dev is a little bit like comparing apples and oranges. GoAccess analyses log files, that is a more robust approach I would say. I wonder how GoAccess can know unique Unique Visitors, guess that is directly mapped to the IP address which should be fairly accurate. An advantage with GoAccess as a website owner is that you can see traffic coming in from users using things like uBlock origin which is pretty widespread actually.

With counter.dev you have some metrics that you do not have with GoAccess like for example device type, the country of the users and some other minor things. But the biggest advantage is that it is easier to integrate. There are a lot of people with something like a Wordpress site for their restaurant that email me asking how to add counter.dev's tracking script into their site. Many people don't have access to their log files and I think it would be impractical for them to literally compile their analytics tool.

So if you are happy with GoAccess and have it set up you don't need to change.

But if you want to try counter.dev you get your tracking script after just registering with a username and a password. Then put the tracking script in your site and that's it.