Make it SO hard to get more than 1 - 1.5 cents of value per mile. (milestalk.com)
We also found that business class seats will generally get you better value per mile than main cabin tickets. (valuepenguin.com)
If you can use your airline miles when you need to book one of these expensive flights, you will receive several cents in value per mile redeemed. (mybanktracker.com)