I sometimes try the odd radio app that I come across on playstore but find most to be not that exciting or beneficial to my needs or requirements. I recently tried QRZ assistant and I quite like it so far. The best bit is the built in compass that moves to the coordinates of any station that you look up. I think it could be fun and useful for anyone using rotatable antennas and their smartphones, perhaps from a portable location away from a pc. It's also free!