Having had a full day with the HTC 8S I've made some observations about the Microsoft's new mobile OS and how it compares to it's predecessor and competitors.
Well the biggest visible change is the ability to resize live tiles on the home screen. There's also customisation of the lock screen, using different photo repositories and choosing which applications can display lock screen icons.
Otherwise there's little change on the face of things. It looks mostly the same and works in a similar way.
Performance is good, but side by side with a Nokia Lumia 800 running WP7 everything was just a hair slower on the 8S than the older OS.
The camera lens feature works, but is gimmicky and had been available on Android devices for a while. There's allegedly improved multi tasking, but in operation there seemed to be little difference. In theory Skype should be fully functional on WP8 but in practice notifications and calls work sporadically. It will certainly be a pleasant addition to the Microsoft armory when it comes out of beta, although none of the low end WP8 phones announced so far have front facing cameras, so video calling will be off the table for them.
Whilst Windows Phone 8 is nice upgrade, as yet I see no compelling reason to select it over Android (for flexibility and choice) or iOS (for massive app support).
Windows Phone 8 does offer a beautiful user experience and excellent usability. However WP7 also offers these features and high end phones running the older OS are available for around half the price of a low end WP8 device. The latter may offer some better upgrade options, but right now unless you need the high end features of the Lumia 920 or HTC 8X I'd recommend searching out a bargain on a WP7 device instead.