I'm still on the fence about keeping this card: I'm thinking I might be better off just cancelling it and getting my annual fee back.

Does anyone know what happens if you make a purchase (one last hurrah at Walmart billpay) and then cancel? I guess you'd lose the miles if they haven't yet posted?

Honestly, it's kind of too much trouble for too few miles now for me to keep hitting the Walmart service desk. I suppose the "trouble level" depends on how humane your store is.