What is the difference between factory unlock and r sim unlock in iPhone 5?

What is the difference between factory unlock and r sim unlock in iPhone 5?

Factory unlocked iPhones are iPhones unlocked by apple, that is you can update the software without any problems and you also will get apple support.

r sim unlock is a hack-unlock for iPhones. Using this route to unlock will allow you to use the phone with any sim but every time you update the software on your iPhone you'll need the r sim to unlock it to use with sim card other than the one the iPhone was sold with by the network provider. This methods voids the apple warranty and people also have reported of unstable iPhone. The phone heats up or sometimes it freezes.