Reference-counting in Objective-C is probably an improvement compared to the very basic memory management of C++. (C++ fans, yes, RAII is better than nothing, but no, it's not enough.) But ref-counting is also a far cry from the tracing garbage collectors most of us expect in a modern language.

There are plenty of gotchas in non-GC'ed Obj-C memory management, see my previous comment in a different thread: http://news.ycombinator.com/item?id=1986799 . Also, the interaction of ref-counting with multi-threading is just awful: objects that some code uses but doesn't own must be obsessively retained-and-autoreleased in case another thread preempts and releases them. Behind the scenes, this takes and releases a lock on the object, which doesn't exactly help efficiency.

I'd rather hear about more of the things that Objective-C really gets right, instead of another "omg, I'd never heard of ref-counting before!" post. Here's a couple to start people off:

* Using named messages (instead of vtables a la C++) provides quite good introspection and run-time modification of the class hierarchy. This allows cool features like "delegates" that implement a subset of extension behaviours, and method forwarding.

* Objective-C's "informal protocols" are what we'd now call duck-typing.