The Skype and Google Hangout trial with my group was very interesting and inspiring. I only used Skype for work-related purposes before, such as a job interview, consultation, etc. It was fun to talk while watching the videos of my group members. I found that the sound quality of Skype is great.
I did not know about Google Hangout at all before. I was surprised that Google+ provide a number of good tools for free. While the hangout, my group shared a Google Doc, which worked better than Blackboard's white board. However, Blackboard seems to be more appropriate for a large online class, because it can control who can speak and create participants into small groups.
Each tool has its strenths and weaknesses. However, we may run into technical problems anytime using them. It is important to expect technical difficulties and provide technical support.