Not to be picky, but this is only about nav bar design (which the article title fairly points out.) It's helpful to the aesthetically-challenged, for sure.
As an App developer it's always hard to come up with a good visual design, especially if you have a lack of Photoshop skills, like in my case. So it is great that someone else does this job for a real fair prize. I bought some beautiful designs and got always a perfect support in case of questions. So for all developers who share the same situation: Try it out!
I love all the nav bar designs here! However, I wish you'd come out with some flat/minimalistic design elements soon!