The main reason I decided to go with Blogger was simply because of its ease-of-use. It may sound cliche, but in all honesty, Blogger–out of all of the options listed–was just the one that seemed to me to be the easiest to grasp. What's more, as a relative newbie to this whole blogging thing–as evidenced by my blog that I created last week–I can personally attest to the fact that Blogger is very user-friendly and not overwhelming in the slightest, meaning that as a potential tool in helping patrons/teaching students/delivering presentations/etc., it could be extremely handy.
I liked a few of the other options on the list–Quora was decent, and I almost went with WordPress, which had a similarly easy-to-absorb interface. On the whole, though, Blogger was just the one that I came away from the most impressed with. It's a testament to Blogger's design that I already feel completely comfortable with how to use it.