Appealing/Appalling finds the beat with Jay-Z, Katy Perry

The mobile application market is growing at a breakneck pace and shows no sign of slowing. Thus, FierceMobileContent is offering a new feature to help make sense of it all: Appealing/Appalling is a weekly spotlight on the best and the worst that mobile developers have to offer, from games to navigation tools to augmented reality solutions. This week, in the wake of the Grammy Awards, Appealing/Appalling takes a sampling of a pair of music-themed apps spotlighting two huge pop stars--Jay-Z and Katy Perry--and finds one to be music to the ears and the other an off-key mess. Special feature