For me, I've basically dropped HotCocoa. After doing a few apps with it I quickly came to realize that I liked IB and building apps that way. The thing that I've missed from HotCocoa is all the little Ruby-ish extensions that it added to various classes. As I've built other apps I've been collecting up a few of those and decided to stuff them into a gem.
You can see them at https://github.com/dj2/Bean if you're interested.