PIXELSPRING It's an excellent way to create iphone apps without the drudgery of coding in Obj C. Having said that, it's possible to use Obj C in addition to javascript - which makes it incredibly powerful. Previous to using Nimblekit I was writing my own code to utilise a local browser but Nk speeds up the process hugely.
So why did I choose this over free alternatives - in a word, support. The dev is incredibly helpful and responsive to users requests and questions and this alone warrants the price. The code is updated frequently and new features are constantly added.
As a way to combine native interface elements with the ease of html/css/javascript it's unsurpassed!
(Version 1.5.5)