It is going well for me. I definitely prefer this form of interaction over the built in commenting functionality. I do have IntenseDebate running on another blog and there are aspects of that service that appeal to me (I like the OpenID integration for one thing) but I don't have many comments on there to be able to assess its functionality compared to Disqus.
I would like to see more options on the backend of Disqus but I was told that an improved backend is in the works for Disqus so I am happy with my choice. I do like the fact that if I remove Disqus all the comments I have received remain in the blog (I didn't know that when I installed Disqus) so there is really no harm in trying it out.