There's so many things to like about this sort of system:
1) Someone else can deal with the signups and spam, not me.
2) Someone else can deal with the never-ending comment feed bot traffic, not me.
3) My content stays mine and separated from a third-party commenting system. If I decide I don't feel like having comments again, I can take them off my site, but commenters keep their contributions.
4) Integrated community troll tracking makes it easier to weed out the morons.
5) The comments, I think, will remain out of the search indexes, keeping results focused on my content, not random combinations of comment text.
Sorry for the extra ads lately, but I'm trying to bump up the daily earnings from the blog, and it's working, so they're staying. My full-content feeds and the front page remains ad-free however, so feel free to subscribe and/or read the front page only.