I'm not a big fan of mobile mining apps even though my only experience with one was overwhelmingly positive.  I recall back in the day when Litecoin was first released.  I downloaded some sort of Litecoin solo miner on my old iPhone and actually managed to mine a block.  I remember thinking it was pretty cool, but back then it wasn't exactly winning the lottery and I was worried about overheating damage to my phone so I stopped.  Looking back, I should've probably bought 100 more phones and had them all solo mining.  LOL