ripped from a post by Bruce over at the official forums:
If you are running a slow machine (one that cannot meet the standard deadlines) you should set the advanced configuration to a preference for GAH which will select unscheduled Tinker WUs. If it's a medium speed machine or better, the default preference for FAH will be fine.
All of the schedules just changed, along with the points, so all older recommendations for preference settings are probably obsolete. We need some time to see how the new points and the new schedules influence those recommendations.