Open Source vs Closed Source

We use several different types of software each and everyday whether it be apps on our smartphone or the operating system on our computer.  The software that we use is either open source or closed source.   Some examples that come to mind are apple and android.  Apple locks down there software so that no one can look in modify it or change how it works.  Android on the other side is open so you can look under the hood so to speak and see how everything works on the inside and change things around potentially.  Each type of software has there pros and cons.  Closed source software is generally more secure than open source however it is harder to develop apps for/on because those companies can require developers to buy expensive licenses.  Open source applications can be less secure since they allow you to see how the application works, however this means that users can more easily customize there phones and easily build custom software for them.  Recently someone replaced the Linux Mint iso with a hacked version that had a back door this shows how dangerous open source software can be.