@Blase, I have the Barclaycard Arrival and agree, it's great for travel, with the rebate and all. Plus they waive international credit card transaction fees (which can add 3% extra on top of your purchase). So it makes even more sense for booking things like European train travel, prepaid transit cards, hotels, cars, and regional flights.

My SPG AmEx is about to start waiving international credit card transaction fees this month. So I'll have to balance these two cards against each other and see who would win in a fight. The SPG AmEx card signup bonus is super sweet, but after that you have to spend like $30K with them annually to reach the lowest SPG tier (Gold) that gets any worthwhile benefits. I wish I liked Starwood hotels a little more...some of them are pretty good, but others just aren't, especially for the price.

As Blasé says, the nice thing about the Barclaycard Arrival is that you're not bound to one hotel chain or airline group. Also you don't have to get to some rarefied level to start getting real benefits from it. So I guess I may have just answered my own question, at least for my own purposes: the Barclaycard would win.