TBreak has an overview of the top five new features of Apple's iOS 5 over here.
Considering the popularity of BBM in the region, this is probably the most awaited feature by iPhone fans and one that has BlackBerry users worried. Like the BlackBerry Messenger, iMessage will allow iPhone, iPad and even iPod touch users to send messages over WiFi or 3G. You will be able to send text, photos, videos, locations as well as contacts and like BBM, get delivery reports and read receipts. What is not supported yet is Group Chats.
Additionally, the site also published a list of the top five new features of Mac OS X Lion, you can read this article over here.
1) Mission Control
Mission Control brings together full-screen apps, Dashboard, Exposé, and Spaces in one new feature that gives you a bird’s-eye view of everything on your system. With a single swipe on the trackpad, your desktop zooms out to Mission Control. Think of it as the hub of your system: View everything and go anywhere with just a click.