On particular blogs, I found the guest posts more enjoyable to read and helpful, even if they weren’t tailored to the blog – experiences blogging, in-depth reviews/tutorials of services, and the like – in some cases, with more experience than the blog owner.

So far, I’ve only had two guest posts on my site, and I have another one coming up soon – but they are the exception rather than the rule. This means that virtually all of my site content comes from me.

I think you can get away with publishing excellent guest posts – either on a par with your own posts, maybe even slightly better. I see your point about not putting other people’s posts on your site if they are better than your own, but on the other hand, I’d like the guest posts to be great, too. With this in mind I made sure that the guest writers for my site would be writing about things where they knew more than I did on those topics. I think it’s better to do that than publish a bad post because you don’t know the topic.