What McCartney was testing was availability a few months out -- specifically, next June and September. My own "tests" were of a similar number of days out. Delta inventory is just horrible in such situations. Delta DOES release award seats 330 days out, the traditional release date now abandoned by some airlines, which MAY explain why their availability looks so terrible if you look 90 or 180 days out. On the otherhand, I will say I've played Delta's 330-day-game and it's not like inventory is plentiful then, either. I'd be amazed if they made a similar number of standard award seats available as UA or AA.

Regarding US, my guess is they would be terrible for int'l and Hawaii seats, simply because they have fewer such flights in their system than most of the major airlines. Fewer seats to popular reward destinations for about the same number of customers is a recipe for problems. McCartney also found them below average for domestic awards, too. My own experience was that they were not materially different domestically than, say, CO. Obviously, your mileage may vary!