Hi I'm looking to buy a galaxy note 2 or should I keep my iPhone?
1. If you want a simplistic answer then make a priority list of your phone uses - voice calls, texting, music, movies, email, web, navigation etc. If voice calls, texting and (unless you have an irrational hatred for iTunes) music are at the top, stick with the iPhone. If email, web, navigation are at the top, get the Note.
Rationale: the Note II
is mainly a two-handed proposition, so if you're one of these people who can't walk down the street without talking or texting on your phone, it may not be for you. Also, I'm sorry, but music on Android is just not as slick as in the iTunes ecosystem. Not saying it's unusable, but at a minimum you'll have to experiment with several players and sync solutions to find one that works for you. However, for web and navigation, the screen size blows the iPhone out of the water, and Apple Maps is still playing catchup with the fullblown Android version of Google Maps.
Then, of course, there's the stylus, which is in a different league to the prosthetic fingers you can buy for iOS.
2. Do you have a large investment in iOS Apps or DRM-protected iTunes movies (iTunes music shouldn't be an issue since they dropped DRM years ago)? Check that any Apps you rely on have decent Android equivalents.
3. Do you have any philosophical objection to using Google for your contacts/calendars management? Contact & Calendar sync with Google works well with Android, iOS and MacOS. You don't have to use gmail as your primary email - the Samsung email app supports all the usual protocols - but the true Google way of doing it is to let Google check all your email accounts so that you can read them through gmail.
4. How do you carry your phone? Cut a bit of card or styrofoam to the size of the Note II and see how it fits in your pocket. I have no problem but your wardrobe might vary.