What does Google Hangouts do well? Easily to set up a video call. Sending messages is more realtime.
What does Google Hangouts not do well? Send reminders and notifications
What do you wish you had known about Google Hangouts before using? Nothing - it's very self explanatory!
Have you used a competitor to Google Hangouts? If so, how does it compare? Yes, I have used Skype and Joinme... and I find Google Hangouts to be the easiest to use and most user friendly with advanced functionality