I think a blog without comments is like having a BLT sandwich without the bacon or tomato. Comments on a blog show that an active community is watching and interacting. When you disable comments on your blog I personally feel that you are missing out on important interaction with your readers.
That being said, it is important to know that I allow commenting on my blog, but I do moderate comments. I don’t post comments that are blatant advertisements for other people’s business, and I do not allow search engine “follow” links on my comments until you have posted comments a certain number of times. Once you comment to hit my threshold, comments on my blog that you leave will be followed by search engines.
I use a WordPress plug-in called Lucia’s Linky Love to control the follow nofollow attribute on links left in comments on my blog and in the commenter’s signature block. I have found that by allowing comments, within my parameters, that I have increased the amount of commenting on my blog and have actually quadrupled my RSS feed subscription readership.
If you are so tightly controlling interaction on your blog by either not allowing comments or deleting any comments don’t match your personal point of view, I feel like you lose what a blog is all about. In any one community not everyone will agree on everything, but if you as a business owner allow interaction between yourself and even between commenters you allow for an overall “richer” experience for every blog visitor.