Since switching from Android to iOS, I’ve been looking for an instant messaging client that works well with Google Talk. Push notifications are essential for the “instant” part of instant messaging.
Unfortunately, most iOS Talk apps only have push capability until the application times out in the background (10 minutes); One client, Verbs IM Pro (App Store link), has server-based push notifications, but it times out after a week, and has some bugs and reliability issues. The developer hasn’t updated it for six months.
Google now offers a Hangouts app for iOS (App Store link), and it works very well. Most importantly, it has server-based push notifications that don’t time out. I’ve tested it by killing the app in the system tray. It’s really nice to have a way to keep in touch with friends without using SMS or iMessage, and it works well in conjunction with the built-in chat in Gmail and Google+.
If you want to use the new Hangouts app with a Google Apps account, your administrator will have to enable it for your domain first. Here’s the Google support article. Eventually, Google Talk will go away, so this is an early opt-in.
It’s unfortunate that Google ditched the standards-based XMPP protocol used by Talk. I’m not sure what this means for the future of third-party IM clients. If iMessage is anything to go by, there may never be any.