I gave posterous another chance. I have to say I'm loving the feature to post to multiple sites at one time. This way all my social networks and blog can be updated at one time. I have to say this is a really neat feature.
It will make posting so much easier not having to go to tons of different sites to post things. Plus, I added the share button on my bookmark so if I find something I like I can easily share it on my blog and social networking sites.
You can have multiple accounts on one e-mail and that is a feature I love. Plus, you can import which is a feature tumblr does not have that I wish it did. In that area it's far behind.
So I say give posterous a try. You don't have to abandon your other blog or social networking sites it might just make things a little easier.