How is the quality of Hello Mobile calls?

I'm using KT for iPhone 5.

I'm thinking of changing my phone to Hello Mobile.

I'm curious about the quality of the call, how is it for those who have used it?

I wonder what are the other advantages.

Especially the accentuating part~

1354 2015-10-17 Lady

popular How can I resolve TLS security configuration errors?

popular Do oats also have side effects?

popular How do I recycle and recycle foil like cooking foil?

popular Why does it say that your license has expired on your phone?

popular Can I listen to music with Bluetooth earphones on the plane?

Same Tag Can I join the Galaxy S8 as a mobile carrier?

Same Tag Can I use melons on two devices?

Same Tag Do I need an existing phone when I open a new phone?

Same Tag Why is the Xiaomi robot vacuum cleaner not connected to Xiaomi's home app?

Same Tag Please recommend a good weather app

Same Time I'm using a mop, but I can't clean it up

Same Time How is the quality of Hello Mobile calls?

Same Time I keep getting a message to activate Windows 7. What should I do?