Understanding the differences between FACTORY UNLOCKED and SOFTWARE UNLOCKED
FACTORY UNLOCKED Because these have been officially & legally unlocked by Apple directly at the factory, these iPhones can always be updated with original firmware without the risk of getting locked again. This is a big advantage and trouble saver. Officially & Legally Unlocked by Apple means that the IMEI number has been registered as being "unlocked" in the Apple database, so you gain access to all of Apple's services just as any other original iPhone does.
SOFTWARE UNLOCKED These kinds of phones were previously locked units that were unlocked "in-house" style, usually by 3rd-party software. Upgrading firmware or restoring the unit to an official iPhone firmware will result in the unit being brought back to a carrier-locked state which would disable many features of the phone.
Some of the phone features are:
* A faster 600MHz CPU and double the RAM at 256MB * Faster performance * Faster network speeds of HSDPA 7.2Mbps * 3.2 megapixel auto focus camera with VGA@30fps video recording, touch focus with subject tracking, macro mode from as close as 10 cm * Digital compass with automatic map orientation in Maps app * Better audio quality (as recorded and analyzed in our office) * Louder loudspeaker results (with performance gains primarily in music playback) * Purportedly better battery life * Oleophobic display coating supposed to make fingerprints easier to clean * Text-to-speech feature called VoiceOver is included in the new Accessibility menu * System-wide Screen Zoom is also included in the Accessibility menu * Voice Control, speaker independent. Can be use to call a phone number, play music by song/album/artist name, shuffle music * Built-in support for Nike+ jogging system * TV-out outputs 480p instead 480i resolution