I like Johnson to the extent that he does not want the government doing things I don't want it to do. But he also does not want it doing things I want it to do. I would not have voted for Ron Paul and I don't intend to vote for Johnson.
I'm more ambivalent about Stein. I think I agree with her on almost every issue. So if I decide to send Obama a message that he ought to fight for progressive goals, she would get my vote.
That's my answer to Jeff's question. But I'm far from clear about whether I feel that message to Obama is as important as telling Romney that I vastly prefer Obama to him.
I am sure Obama will win DC's electoral votes, and the electoral vote determines the election. Nevertheless, I think the popular vote has important symbolic weight, and for that reason, I lean toward overlooking those things I disapprove of (mainly things Jeff has spoken of more knowledgeably than I can), and voting for Obama.