Microsoft this week announced Windows Phone 8, its brand new mobile OS designed to work hand in hand with Windows 8. Making the choice between one platform and another is tough, but in our experience Windows Phone fans love their Windows smartphones.

As we know there is no way of upgrading from Windows Phone 7 or Windows Phone 7.5 to Windows Phone 8. But you can update older Windows Phone handsets to what Microsoft calls Windows Phone 7.8 - a platform whose home page looks similar to the new OS. And we also know that Windows Phone 8 will appear only on new, high-end handsets. So if you want to get Windows Phone 8 there will be a price to pay, either now or when you reach the end of your current phone contract. See Windows Phone 8 review.

You can find out when the first Windows Phone 8 smartphones become available in our story: When can I get Windows Phone 8?

Windows Phone 8 is based on Windows 8 and therefore shares the same Start Screen with adjustable live tiles. The move means that there is effectively a single platform for all Windows smartphones, tablets, laptops and PCs.

New features in Windows Phone 8 include support for multi-core processors, higher resolution screens, microSD cards and NFC sharing. Pre-installed apps will include Internet Explorer 10, Wallet and Nokia Maps.

But is it worth upgrading to Windows Phone 8? Windows Phone 8 has been extended, further developed and improved compared to version 7.5. We've taken a look at the new features and changes so you can decide.

Upgrading to Windows Phone 8: an easy change

Nokie Lumia 820 If you use Windows Phone 7.5 you'll easily find your way around Windows Phone 8. The home screen with the familiar tiles featured in Phone 7.5 and Windows 8 is once again the place where it's all at in Windows Phone 8. Another familiar relic is the list of applications that comes into view when you swipe to the right from the home screen.

Windows Phone 8's home screen closely resembles the one found in Windows Phone 7.5, but at the same time it offers more functionality and possibilities. For example, in 7.5 tiles could be either square or rectangular, meaning you could display one or two tiles adjacent to each other. In Windows Phone 8 tiles can have three different shapes. In addition to the square and rectangle, there is a smaller square size available, which is exactly one quarter the size of the 'old' square. Thanks to the new addition, it is possible to have a lot more apps visible on the home screen without having to swipe.

Not all apps can use all three sizes; many apps can only be displayed as either a small or normal sized square, but not as a rectangle.

There are more improvements to the way you can customise your phone, and the lock screen also offers new options for this. In Windows Phone 7.5 you could display the time, an upcoming appointment and information on missed calls and new messages. Windows Phone 8 gives you more freedom to customise the lock screen as well as the option to show previews of the most recently received email. You can also show messages from Xbox Live friends and game notifications, for example.

Upgrading to Windows Phone 8: under the hood

HTC Windows Phone 8 Under the hood, Windows Phone 8 is no longer based on Windows Mobile, but rather shares the same codebase as Windows RT, the 'trimmed down' version of Windows 8 developed specifically for energy efficient ARM tablets. A big advantage that comes with that change is ease of portability of apps between Windows 8 and RT to Phone and vice versa. It also means the hardware support has been greatly improved.

While Windows Phone 7.5 only supported older single core processors and 800x480 pixel displays, Windows Phone 8 theoretically can operate with 64 processor cores and support displays with 1280x720 and 1280x768 pixels. Another hardware feature that is now supported is a flash memory card reader, meaning it is finally possible to have Windows phones with a micro-SD slot, something sorely missed in Windows Phone 7.5 devices.

Upgrading to Windows Phone 8: 5 key new features

We've explored this subject in detail in our feature, 'What's new in Windows Phone 8? 5 new features in Windows Phone 8'. But here in brief are five important new features.

Windows Phone 8 is about to get a whole bunch of key new apps. Indeed, Microsoft has made the SDK available for developers, and claims that soon 46 out of the most popular 50 apps on other platforms will be available for Windows Phone 8. Because the ladder has been pulled up behind Windows Phone 7.5, these apps are unlikely to work on that platform as well. So you need to upgrade if you want an app for that.

Also potentially important is Microsoft's Data Sense. These feature of Windows Phone 8 not only allows you to view accurately how much data you have used from your monthly allowance, but also utilises compression and Wi-Fi technology to reduce your data comsumption. Given that new apps and multi-tasking are likely to lead to you utilising more data, this feature could prove crucial. But you won't get it on older versions of Windows Phone.

One for the parents is the feature Kids Corner. This setting allows parents to set up an account for their children that allows them access only to age-appropriate content, and stops them from being able to change or break the phone.

A similarly family friendly feature is the People Hub. This is in essence the Contacts book of Windows Phone 8, but it also allows users to set up 'Rooms' which offer shared access to content and communications to only specified users. So you could have a family Room into which only family members can post and message each other.

Of course, the biggest thing in Windows Phone 8's favour is the billion or so people who use Windows on PC, laptop or tablet. And Microsoft is determined to make a great deal out of this. If you use Windows 8 and a Windows Phone 8 handset you can access all of your content: office documents, photos, and music - wherever you are.

Key to this is Microsoft's SkyDrive cloud computing function. Using Windows Phone 8 and SkyDrive allows you to move files and apps from PC to tablet to phone to Xbox, according to Microsoft. SkyDrive is built right into the PC and the phone, and is available on the Xbox as well.

If you create a new document with your phone, it can be accessed on your laptop, PC or tablet as well. SkyDrive also supports voice notes. You start with 7GB of free space, and you can pay to add more so you don't have to worry about running out of space.

Similarly you can access Xbox Music service from a Windows Phone 8 device, and this will place your favourite tunes wherever you want them - via Windows PC, Windows Phone and Xbox. But your handset will need to be a Windows Phone 8 device, as older handsets won't allow this.

Upgrading to Windows Phone 8: verdict

If you are a Windows Phone user, and you don't wish to change to Android or iPhone, you will want to upgrade at some stage. Whether that time is now will depend on how important the new features of Windows Phone 8 feel to you. If you are a parent of young children, Kids Corner will seem attractive. If you purchase apps, in order to future proof them upgrading will be something of a saving. And especially if you are a Windows 8 user, access to your PC via your Windows Phone 8 device will make a lot of sense.

HTC Windows Phone 8