There is no contest: Walking is easier than running (for me). There is no fear associated with it, I don't have to talk myself into it, it's relatively easy, and, the best gift: there is no pressure to perform. I've walked 2 miles a day three days this week, and plan to walk every day, gradually increasing the time and mileage.
The rewards are tremendous. You're outside, you're free, it's free, you can do it in ANY kind of weather, even in the worst winds, if properly dressed. You can evesdrop on people's conversations. You get to pass people! You notice the little changes in the flora and fauna. You see wildlife! (One bunny, one deer.) I have no concern whatsoever for my pace! Um, OK that last one is actually a lie.
My first two walks clocked in at 17:30 min miles. Yesterday, I did 16:00 min. miles.
Who says I'm competitive?
UPDATE: Speaking of competitive, check out Thomas' account of his first ultra. Thomas is a riveting writer, and includes such details as him running up the "Devil's Kill Me Now" hill, and many other descriptions of Irish places with fanciful, and terrifying, names. He finished in the time it takes me to lace up my shoes. Thomas, you're amazing!