Using that too now. Could do with collapsing threads and skipping to next / previous top level comment and I'd be a little happier. But otherwise quite pleased.
What do you mean by collapsing threads? Currently if you clicked on a comment, it should collapse said comment and any children of the comment.
With regards to navigating to the next/previous top level comment, worth putting that as an "issue" on Jerboa's GitHub as a feature request if one doesn't exist for this feature already.