A) Changing previous entries to reflect changes in product models and prices
B) Adding the best/most useful new products that have come on the market in the last year
C) Adding information on apps and hardware that can help in smartphone/tablet-based video production
D) Adding a section on products that can help in sharing and distributing mobile media
You can check out the updated document here.
If you are more interested in which mobile phone you should purchase check out How-To #1: Choosing a Phone.