The 4g and the processor speed on the Galaxy iii are awesome. There have been significant updates to the usability of this device with respect to previous Android offerings. My main gripe is the Google Music suggested Android file transfer program does not work, so synching your music must be done through kies, which is not terrible to use.
The large screen is easy on the eyes, and the voice recognition is quite good. A little awkward when typing in horizontal position, but typing in vertical is easy enough that you may not care.
