Which phone you want out of the two that you've picked really depends on what you use your smartphone for and what you expect from it. I am a Mac-owner myself, but I carry an android-based phone (Galaxy Nexus, to be specific). One thing that you should be aware is that the only media content that you've purchased from iTunes that will work on non-Apple devices is music. Things like movies and TV shows are protected by a code planted in by iTunes that basically make them accessible only through iTunes.
So if you have a lot of videos you've purchased from iTunes that you would want to watch on your phone, and you are a heavy media consumer, then you should definitely stick to purchasing an iPhone 5.
Another thing to note is that Galaxy Note 2 is a niche device, and is not exactly designed towards average consumers. Yes, the phone is beastly in terms of size, and everyone I know who has this phone - fans AND haters of Samsung - have admitted that its bulk does make carrying around a bit inconvenient. Also, it has a plastic body that a person who is used to the fancier build quality of Apple devices may dislike. I've held it in my hand and, while it does feel sturdy, I have to say, iPhone 5 does feel like the more premium device. With that said, the ergonomics on the Galaxy Note 2 is better, largely thanks to rounded edges that will allow your fingers to wrap around the back of the phone without crossing sharp corners (as you would on the iPhone 5).
The reason why Galaxy Note 2 is a niche device is because of the combination of its size and S-pen functionality. Average consumers have called the S-pen functionality built into Touchwiz UI over the stock android OS a bunch of gimmicks. On the other hand, there are consumers out there who do find the S-pen to be useful. If you do a lot of content researching & sharing for work, for example, then there are some things you can do with S-pen that will allow you to do part of your work on the phone. Also, Galaxy Note 2 comes with a huge battery (3100 mAh) that you can also swap for another one if you are a heavy phone user. It also comes equipped with microSD card slot for expansion of available storage space.
Before I finish, I should add here that Android OS has a steeper learning curve than that of an iOS. It will also take you time to get around all the features of TouchWiz and S-Pen. Some people like Android OS because it does give more power to consumers to truly make their phones their own, but some people just prefer everything to be set up for them. If you think you are the latter type of person, then you might want to get an Android device - not just Galaxy note 2, but other great android options such as HTC One.