I think the results may vary and isn't reflected in the WSJ's test.

I have had far more success in DL and NW in redeeming domestic coach awards than UA. In fact, I have tried for nearly 5 years to redeem a domestic coach award on UA with successful only this month! WN is, by far, the easiest to get a seat.

The trips that I request usually have a Sunday return, which are hard to get. DL doesn't have a Sat. night stay requirement so I sometimes use it for midweek redemptions. If other airlines want to cut down on redemptions for business trips, they should consider 14-21 days advance redemptions and not a Saturday night stay because the Sat. night stay puts too much demand on Sunday returns.

As far as international trips, my success rate is about the same on all the airlines.