I've built up more Delta Skymiles than the law allows, mostly due to my inability
to find reward travel at a decent redemption value.
Seems like they are always "out" of the Skysaver seats, but you can usually
find seats at the higher Skychoice cost.
They've recently included the other Skyteam airlines on the Delta site so that
you can use Skymiles on other airlines without going through a Delta agent.
Hopefully, now it will be easier to use Skymiles since, theoretically,
there will be more seat availability.