are upgrade versions all the same ?

now that windows 8 pro is officially available in various versions eg. upgrade,upgrade (£14.99 version for computers 1 year old or less) and i have also seen in the shops they are selling windows 8 pro upgrade and windows 8 pro upgrade pack, when i asked i was told that windows 8 pro upgrade pack comes with media center included for the same price. i dont know if this is correct or the sales assistant didnt understand the difference.

my questions are :-

whats the difference between the upgrade offered for £14.99 UK pounds offered with computers less than 1yr old or less and the normal £25 upgrade version.

based on versions bought via the upgrade assistant online, are they all the same download size ?.

It is my understanding that the Windows 8 pro upgrade is for eligible purchases of Win 7 machines to upgrade to Win 8 pro. the Win 8 pro pack is to upgrade machines that came with Win 8 to pro version.

For the consumer their are 3 version of Windows 8
Windows 8
Windows 8 Pro
Windows 8 Pro w/media center.

The 2 online updates are the same and is Windows 8 Pro to upgrade from XP, Vista, Win 7 and they are offering a Media Center feature upgrade for free.

At retail you will see.
Windows 8 Upgrade - Upgrade from XP,Vista, Win 7
Windows 8 Pro Upgrade - Upgrade from XP, Vista, Win 7
Windows 8 OEM - which is the full version and can be used for Personal Use.
Windows 8 Pro OEM - which is the full version and can be used for Personal Use.
Windows 8 Pro Upgrade Package - which upgrades from Windows 8 to Windows 8 Pro w/Media Center

Jim

so how do we tell the versions apart when choosing which to buy ?