For 99p you get an app thats had a lot of work and will be constantly updated with the latest sets. I would say thats a bargain, works great for me.
I know why more is coming out for android over iphone:
fact is apple make it so hard to publish onto the apple store whereas google make it so easy for android.
I did notice an app has finally come out for the iphone thats a mini-figure identifier for new collecters sets where as the android has had 2-3 out for ages.