The problem with those is no one I know uses them, and they're generally happy with Twitter. And I don't disagree with them.

app.net wanted more than I could afford to follow more than a few people, but the others look interesting. I'll give them a look.

edit: ello won't accept my email for the invitation request. Quitter looks like a clone of Twitter, and barely anyone in the public timeline speaks English. Not sure what to do with this.

edit 2: It looks like it took the request and sent me ten different confirmation emails while showing an error on the form. This doesn't make me feel good about the service.

Or, better yet, pump.io or identi.ca, federated services which can be bridged to Twitter.