Hangouts for iPhone and iPad is Google's new cross-platform messaging app that lets you converse with your friends regardless of what phone, tablet, or computer they are using. It features a beautiful, clean design and support for video messaging.
The chat view in Hangouts is very traditional and flat with some subtle shading. Your messages and picture are on the right and everyone else is on the left. All users' chat bubbles are the same color, so only the picture distinguishes users from each other; something I actually like. It's simple
Tapping a user's photo will take you to their profile which includes everything they've made available on Google+, including work history, basic information, education, and more.
Video chatting with Hangouts is super easy, looks great, and also sounds crisp and clear. I had a quick conversation with Rene while he was in a noisy environment, yet I had no problem hearing or understanding him.
Google Hangouts also gives you control over who gets to hangout with you and who must send a request. You can also choose to automatically snooze notifications after 1-72 hours and block specific users.
Group conversation support
Video chat support
Get notifications only once. After you see an alert, it disappears from other devices.
View collections of photos shared from each Hangout
Connect to Messages for Mac with Jabber
Universal for iPhone and iPad
Requires Google+, a simple Gmail account is not enough
Can't set your status/availability
No sound when new message comes in
No SMS integration. This is not a fault of Google, but rather of iOS API limitations, but it's still a bummer.
The bottom line
If you chat with friends on Google Talk or Google+ often, then Hangouts is awesome and you should definitely pick it up.