I'm a long time user of cocos2d too (some 5 years). I've released a number 1 selling app in a few countries and have several projects incompleted.
I've been tempted by UE4 (more so than Unity) because it allows me to upgrade to PC and I'm experienced in graphics, but, and this has been echoed by a few, I too miss coding cocos2d.
With coding you sort of know what to type as you get to learn where things are, also extremely quick compile times - which I must say is down to xcode being great.
With content engines (like Unity) I can't help feel I'm re-arranging the furniture - and not creating anything new.
For me cocos2d & Spritebuilder will always remain my main development for 2d because I can control everything.
However, quite worryingly, as someone pointed out, good income on apps is now quite difficult to achieve.