After playing with it a bit more, refreshing comments seems to be iffy. I had this specific thread open when there were only 6 or 7 comments, and tried hitting Refresh repeatedly later when there were about 10 comments visible in my desktop browser. None of the new comments showed up, even when I backed out to the threads list. I think they only appeared after I did a complete refresh of the threads list and reopened this thread.

Overall, though, it's pretty good and I want to switch over - just feels like it needs a bit more polish first.