I've downloaded it on my Lumia 620 -- in Jordan, Middle East.
Here are my thoughts and facts:
• It is snappier. I used to compare it with a Lumia 820 to test how fast it is by opening the store on both devices at the same time. The 620 used to have some delay, now it doesn't. It pins apps faster, opens them faster and so on.
• Unbranded Lumia 620 (obviously) got data sense. No fm radio.
• Glance screen is there as well as the color profile. I didn't find any option for the double tap to wake (or it doesn't work).
• Nokia Smart Cam is available.