I just bought my first Mac after using Linux for 6 years, so I am speaking from recent experience here. Definitely like Linux, definitely awesome... but it does take some getting used to.
lack of a good package manager is holding it back. sure, there is port, but port's library is tiny compared to its linux counterparts...
Totally correct, my assumption is that Apple is mad that you can install apps without their approval and fees, so they won't bother adding a real package manager even though it's an obvious shortcoming.