That said, I seem to remember a discussion of Condition's fairness.
Right now, waiters are notified in the order of wait() calls. This wouldn't be the case anymore if using a set instead of a list or deque.

Also, I can't remember a situation where I made an intensive use of a Condition (say, hundreds of calls per second), as opposed to Lock and RLock which can be heavily invoked to protect the integrity of critical data structures.