Recs.
Updated
SpecsUpdate
Pros
Pro Group video support
If you have signed in your Google account, Hangouts allows making video calls with up to 10 people or one-on-one. There are business, education and government solutions that increase the participant count to for video calls to 15 as well as offers support for those accounts.
Additionally, you can switch between using either the front-facing or rear-facing camera on your phone or tablet.
Pro Cross-platform
Google offers all features of Hangouts completely free on iOS, Android and web with quick and reliable sync across all platforms. It's also tightly integrated in other Google services - it can be accessed from services such as Gmail, Google+, Chrome.
Pro Completely free
Google offers all features of Hangouts completely free. You can choose to pay for the business, education, and government solutions if you want to increase the participant count for video calls to 15 and get support.
Hangouts app for Android can be extended with an optional dialer for making calls. Most calls to US and Canada are free and international calls have cheap rates.
A Google Voice account will be needed in order have a number that allows these calls to be made.
Cons
Con Lack of end to end encryption
Communications are encrypted between client and Google servers but not from sending client to receiving client. This means that there is still a possibility for someone other than the receiver to read your message if they have access to internal Google servers. But it allows also lightweight chat history search, spam protection and other features.
Recommendations
Comments
Flagged Pros + Cons
Con Is owned by Google
Google is a cooperation that earns money from collecting data and breaching privacy.
Pro Free calls to US and Canada from anywhere in the world
Hangouts app for Android can be extended with an optional dialer for making calls. Most calls to US and Canada are free and international calls have cheap rates.
A Google Voice account will be needed in order have a number that allows these calls to be made.