I' ve seen two Tim Johnson campaign ads on TV lately, and they concern me a bit. The content isn't a problem; they're both pretty much feel-good PR spots. It's Tim himself, or more specifically his speech. He only says a few words, and it sounds like he had to work to get it to sound as good as it does, which frankly isn't very good. Other people who have seen them have said the same thing. (For you out-of-state readers who don't recall, he had a stroke or something like it in December 2006.)
I recall a general concern being expressed when he announced he was going to run again. He really didn't look up to it. People just hoped his doctors and he knew what he was doing. He definitely looks better, although for a TV ad they can do remarkable things in that area. But the fact that his speech is still so obviously impaired is going to be a concern to voters. Tim is generally well-liked (a Democrat has to be well-liked to get elected statewide here), and that may actually work against him. People who see those ads will worry about him and wonder whether he should be trying to get back to the Senate. I saw poll numbers indicating that he's comfortably ahead, but that poll was taken before these ads.
Almost everyone has at least known someone who has had a stroke and the time and effort it can take to recover, if the person ever does. I think those ads are only going to increase public concern about Tim's recovery.