Using something like Chameleon can get you up and running in a very short time. Literally, it took one afternoon for me to get our app running on Chameleon. True story. I actually did it without management approval on the day they said &quot;we should have an OS X app&quot; and demoed it to them at the end of the day. It wasn&#x27;t perfect, and took another week or two to iron out a few bugs in Chameleon we ran into. That was the start of our fork, actually.<p>But it worked, and it would have taken two to three months to get to that point from scratch. I should know, because I did from-scratch ports to other platforms and that&#x27;s how long it took each time.<p>You can mix and match Chameleon (UIKit) and AppKit in the same application, so you can incrementally replace Chameleon with a &quot;proper&quot; solution. If you find that&#x27;s important to you.