I agree with leoemery

If you feel the comment does not add any value to your site, then don't approve it or delete it. As for having links remove all links that any commenter adds

Hello Jsky
You've asked a couple of questions.
One is first impression. May I have the link of the website which the someone has commented? Then I'll know whether your first impression is right.
I also think that how others comment about your site is their opinions. I can only agree or disagree what they have commented. Whether they give a long comment (with almost regurgitating what you've written) or being superior, they are doing their part. What is important to me is whether there's room for improvement for me to take action on, or simply an encouragement for me to be happy about from what they've commented.
Second is ranking. I am not sure whether the unwelcome comment affects your ranking after you've approved for the public to view. Personally, I publish all comments, good or bad, except comments that are vulgar, racist, discriminating, political, or religious thinking.
Third, comments that include plugging in their website. This question also depends on your preference. My experience is we are in a learning and sharing community (at the same time networking, and marketing our blogs). However, to be on the cautious side, I usually visit their website first to make sure commenter's blogs are useful and legitimate. Then I can decide whether to approve or disapprove their website in my comment section.
I hope my response is of some help.
Sincerely, Cheng

Hi Jeanette,

A good comment is when someone comments on the actual content of your post.
It's hard to say without seeing it but, It seems to me as if they may have summed up your post as they understood it and then added a more personal comment on how it affected them.
Sounds like it may be ok and long comments add content to your post as does your reply which also shows engagement, however, I would go into edit and delete any URL to their website that was posted.