There are soooooo many radio apps for iOS that it takes some effort to get my attention. But airadio pro has done that (yes, the app name is all lowercase). This free app is an advanced internet radio tuner that also records what you might want to save and lets you listen later or send them out via email as an attachment.
The app contains links to about 8,500 stations, and they are grouped by genre, or you can search by name. The app supports multi-tasking so you can grab the station you want and do other things while the music plays in the background. You can create a favorites list, and "time-shift" streams by pausing or rewinding.
The app supports MP3, AAC, AAC+v1 and HE AACv2 streams. If a call comes in, the stream is paused and will resume when you are done. You can even select your choice of VU meters, from traditional physical-looking ones, to newer LED bars.
AirPlay is supported as well, so you can get your music out to an external wireless speaker.
The app was easy enough to use, with buttons for genres, favorites, searching, recordings and settings right at the bottom of the screen. Sound quality was good, especially with the higher-bit rate streams, but even low-bit rate streams like BBC News at 32k sounded quite good.
I have a couple of gripes. One is the way of mailing audio clips. You set up your email address in the app preferences, but if I want to send the clip to someone else, I have to go back in and change it. It would be a lot friendlier if I could just type in the email destination. Also, it would be good to use the GPS on the iPhone to find local stations. Especially handy when traveling.
airadio is a clever app that is really full-featured. Best of all, it's free. The app requires iOS 7.0 or later and it's optimized for the iPhone 5. The app is not universal, but runs on iPads.