WP Robot vs buying articles vs hiring someone on oDesk?

Anyone has experience using all three of the above to create new automated content for their blog?

I say go with the hiring someone from outsourcing websites.

Reason?
Simple.
Auto blog is something that I don't trust totally. Though many do but I don't. Well I guess that's my problem !
Second of all, possibility is very high that the ready-made contents will less likely to meet your exact demand. But in case of hiring someone, you have the total power. You have the choice to select someone who can fulfill your exact demand. No fulfilling, no hiring. Simple as that.
Though, if you don't have any experience in this regard then I say go with someone who is highly rated. Otherwise, chances are very high that the low rated writers may scam the sH*t outta you. Good Luck there.

Personally I use WP robot but I have over 100 sites that I am filling content with. There are some good autospinning plugins out there too. But if you only have a few sites you might be better off hiring someone.