Best VoIP for Smartphones?

Hi, everyone.

I recently moved overseas, and I was wondering what the best VoIP application for smartphones to make landline calls was. I've tried a couple of apps such as Skype and Viber (can't do landlines, but great if I'm calling a friend with a smartphone), but I'm not exactly satisfied with the performance.

The only decent one I've been able to find so far was Global Call. The call quality is similar to Skype, but there's one thing I really like about it: if you hang up within 6 seconds of a call, you don't get charged. The only thing, though, is that you can't send text messages with this app (well, that's not too much of a deal breaker for me, I can use other apps for that).

So what do you guys use for making landline international calls? I'd like to try out different ones before settling in on one of them and start using real money.

PS: Here's a link to the Global Call app, you guys should try it out, it gives $1.50 to test it out first.

Android: https://play.google.com/store/apps/details?id=com.lguplus.GCAClient
iOS: https://itunes.apple.com/au/app/globalcall-free-$1.50-credit/id577717588?l=en&mt=8