I think this is a great app. Congratulations on launching!
Sometimes I want to post quotes to Instagram and have had a hard time finding apps that allow me to do a text overlay like yours.
Tweegram is the only other one that I have really found to allow this, but they put an ugly water mark in the lower corner of all your images.
I thought a really cool feature was the ability to move the text around to different positions. One feature I haven't ever seen implemented it the option to add your own photos to the background. I would definitely shell out 99c for that!