I use the ObjC ReactiveCocoa in a big project and, albeit the idea behind it is very nice the lack of debug integration is hard. No the framework issue - but lldb is not good at this kind of tracing... Even, if, to be honest the way RAC is integrated into the app is maybe the issue. The story is a bit better on Swift, because some part of the reactive ideas are "built in"(mapping, filtering), but it still can be hard to understand the flow of the app.