Andy Lees, in charge of Microsoft's mobile phone division, called it 'a new beginning'. Stephen Fry, the well-known Apple fan and smartphone buff, also made a surprise appearance at the UK launch, where he described the new system as a 'joy to play with'. The phone will be available in the UK from 21 October.
HOW I SEE IT - CLARE GIBBINS, ASSOCIATE DIRECTOR, OGILVY PR
All eyes were on Microsoft for the launch of Windows Phone 7. The stakes were high and so was the volume of coverage and commentary.
Despite wi-fi problems and a late start at the press conference, Microsoft CEO Steve Ballmer outlined ambitions and Apple advocate Stephen Fry sang Microsoft's praises.
An embarrassing glitch started on Twitter - the makers of Angry Birds tweeted that Microsoft used their icon without permission and this was picked up by several outlets.
A statement was released, but a quicker and more direct response could have been made.
On balance, the launch has been well received. WP7 is seen as a consumer-led development and a fresh start, and when it becomes available in the UK, I can see it being a success, but that depends on smart marketing - HIT.