Not to mention you can set up alerts to notify you when C opens up.
The biggest issue with AA.com is that they show SWU for J to F, so when looking at flights they show a lot of SWU available when there are no Y to J actually available. EF allows you to see the Y to J UG's easily.
When I'm looking to book a vacation and want to use SWU I can quickly search multiple destinations by week to available UG's