I liked many things about Posterous. Alas, it doesn't seem to have a revenue stream. Recently, in a desperation move, they tried to become more like G+ -- they even dropped post tags!
I also didn't care for the Posterous bookmarklet -- it pulled in too much of the source material.
Today I'm visiting Tumblr. It and Twitter seem to be the new homes for many of the Google Reader Social Diaspora. For example, both Twitter and Tumblr are on Feedly's one click share panel, but Posterous is an extra click away. That extra click kills. (Unsurprisingly the new Google Reader really only supports G+ well.)
Tumblr has the usual rich text edit options, but for microblogging I don't care too much about that. The bookmarket is impressive; better suited to microblogging than Posterous. The work of creating a Tumblr post from Feedly is very similar to creating a Google Reader Note/Share in the old Google Reader.
Tumblr will create tweets for each post and they do provide a (proprietary) backup. However there's no secondary posting; one of Posterous' best features is that they'll create a replica post on Blogger and WordPress. I've seen mention of ways to repost into wordpress from an RSS stream, or import a Tumblr export file into WordPress, but nothing that looks rock solid.
I like Tumblr, but I don't like the absence of an exit strategy.
Still, it's ahead of Posterous - particularly because of the Feedly support (wish Reeder supported Tumblr!).