#1 Always compose your comment in notepad ::: that way if the blog commenting system rejects it or freezes, you still have your comment. Maybe you could use it as the basis for a blog post on your own blog (I do this all the time!)
If you really think you need a 3rd party comments app, I would say of the various services out there, INTENSE DEBATE has been reliable 99.9% of the time. Facebook comments are very unsteady, apparently targeted toward hardcore facebookers who hang on the social network all day 24/7. Disqus really sucks, and the app like the one the blog below uses work maybe half the time, if at all. And I wonder if the blogger knows about this?#2 Let the blog author know - someway, somehow... maybe just by linking back to the article you tried to leave a comment on... Here's what happened a few minutes ago when I tried to leave a comment on POWERLINE blog via facebook log-in: a bit fat FREEZE!