There are sooo many posts re 4.5 I am looking for a summary. I have an extremely stable 4.3 install so I am looking for a game-changer to motivate me to upgrade

What is the latest (.89 I think)
What/when will at&t release their 4.5 for 8110
What are the 5 top features over 4.3 (e.g. Youtube, HTML email, etc.)
What BES enterprise version must my company use to enable the HTML in 4.5
Any other game-changers?

Thanks "folks" (most overused word by politicians and comedians-is there a diff?)