5.8 is doing the same things on 10.7.4: Skype is suddenly crashing or freezing, especially when accessing Facebook contacts inside Skype via chat or their birthday events.
It's also resulting in high CPU usage, and the fan goes into high speed.
This isn't just a MOUNTAIN Lion problem, it's a problem with previous OS builds as well, Skype.
My guess is that they Skype/FB integration is totally screwed up, causing Skype to hang...
In any event, it's totally un-usable.