Webmiles is not as good as it's commercial's hype, at least that is what I have heard from the FF boards. I was interested in it a few weeks back and applied for the Mastercard, I did not know that they have a $30/annual fee, I avoid annual fees at all cost, then when I called the Mastercard customer service, these people really suck, their services are no where near FirstUSA (even though some FFs don't like FirstUSA's service)or AMX.
Hope this helps.