I've heard good things about Caffeinated Content and YACG. I've used neither.
Humanspinner/Jetspinner/Jetsubmitter seems to be a decent service, but you will end up paying like $10 an article if you pay to have it written, rewritten with spinner context, and submitted, plus $37 a month for jetsubmitter if you want to blast unique articles out to directories. I have only used this a little bit and have not paid for the jetsubmitter service yet. This is not necessarily an autoblog service either.
Right now I'm using Content Boss to publish to my autoblogs automatically, but it costs about $75 a month, which is mad expensive.
There are definitely other autoblog systems out there, but I don't know much about them.