To some extent, I agree with Beckles. All things being equal, the numbers shown would be a good comparison. But of course, everything is not equal. The % of seats given for awards is only one piece of the puzzle. To truly make an accurate comparison between airlines, one would need to know what % of award requests are being filled. I have never seen this information anywhere and doubt the airlines would ever release it.

Without that inforamtion we have to look at other things. Beckles assertion that some airlines offer many more miles through non-flying activities is certainly true and adds to the competition for award seats on airlines like AA. The % of an airline's passengers that belong to the FF program is also a consideration. My guess is that AA and UA have a much higher % of passengers who are members of their respective FF programs than say US or a more regional airline like Midwest Express.

Load factors are also an issue. Delta consistently has higher load factors than other airlines - this may be part of the reason for the low % of award seats shown for Delta.

For what it's worth, I have had the best luck redeeming on AA and UA and the worst on US. I have no experience with DL, but from the infamous class-action suit and from what I've heard from others, it has to be the hardest airline to get award seats on.