I believe you would not have a problem keeping both accounts active: Delta Optima and Hilton Optima. You are correct, Hilton card is a better deal than Delta's, since there is no annual fee for the Hilton card. I had both cards active at the same time last year, and received sign up bonuses for both. As a side note, when I decided not to renew Delta's card because of the annual fee, the AMEX rep told me that Delta also has a "free" card, and all I need to do is to ask for it. I turned it down anyway and just have one card right now, which is Hilton.