I just fancied going down the hosted route for a change, less maintenance, no comment spam to worry about, besides I didn't need half the features Wordpress offers.
There are a couple of feature that Posterous could do with though, like custom slug, easier comment handing, javascript.
I'll manage though, it's a nice change for now.
I didn't like the idea of paying for certain features, mainly to use my own domain. I'm not sure if it'll be a permanent move yet so didn't want to pay only to decide to go back to self hosted somewhere down the line.
There are a couple of feature that Posterous could do with though, like custom slug, easier comment handing, javascript. I'll manage though, it's a nice change for now.