I wouldn’t.
That website is confusing to the average user and makes no sense. Linking directly to an instance, doesn’t matter which, gives them a familiar UI to Reddit, and allows them to click “sign up” without issue. From there they can learn about instances and join a different one.
join-lemmy.org is confusing, and makes it seem like it’s some software you download to the average user.
I find that it very much depends. It was very positive a month ago, but day by day I see a lot more arguing, name calling, and petty downvoting.