my Mileage Plus Mastercard (through First Chicago) has double miles (2 miles per $ spent)plus the miles you get from First Chicago for telephone bookings. I don't like them very much, though---they seem not very well informed.

I have gotten slightly better fares with Expedia than with United's website, this agency or United by phone. (UA by phone quoted ORD/TXL/ORD at $449, and acknowledged a $425 fare but said it was sold out, but Expedia sold me the $425 fare). Maybe Expedia is shaving their commission a little??