I have used jcomments on various sites since Joomla! 1.0. I liked it except that it lacked essential social features such as commenting as google/facebook/openID. I therefore moved to Disqus for a while, until I figured out for myself the many issues that make people hate Disqus.
So back to jcomments then.
Now all these years later, I am disappointed to see that jcomments has not made much improvements to build on its initial good design. It is a solid commenting system but it has failed to update to a more social era.
One example of this: importing from Disqus is a feature that has been requested since 2009, but has been left unadressed and posts about it are just ignored on the developer's forum. For me this is a game breaker obviously, in terms of my own system, but also because it illustrate a lack of development.
So yes, jcomment is good but it only does the bare minimum, which was great for Joomla!1.0 but is no longer enough.