One difference is that Google hangouts allows you to have multi video sessions for free. To do this in Skype one member needs to have a premium membership.
Yup one of the reasons we switched once our team became bigger. Another problem with skype is that if user's are on multiple versions of skype, the text chat gets disabled.
Hangouts on the other hand is quick to start with, free and chat, screen sharing, scribble pad work seamlessly across all platforms.
