Well, for starters, with miles you can upgrade at the time of booking, guaranteeing you a seat if one is available at the time of booking.
At the gate the first determinant is MP status. Beyond that, in my experience, it hasn't made any difference whether you are using miles, 500 mile certificates or HK49s.
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danville 1K
[This message has been edited by danville 1K (edited 12-10-2000).]