I posted a few months ago on why I used Blogger. The main reason for not self-hosting was:
Without starting the whole religious war – yes there are very very strong open source blog frameworks out there; put it simply I’m just too lazy (or too busy) to get the thing deployed, tweaked, secured and customised for my world.. that’s why I’m posting here.
I wanted more control of the content; as well as the ability to control posting, comments, spam etc. I also wanted to investigate using one of the tools in production. What better way than to host.
As for my choice of WordPress – I like the plugin architecture; the post-editor; the licensing works for me. I also looked at several blog comparisions – and it really came down to personal choice.