This vnunet article describes information coming from analyst Gartner, who is warning that without a big Symbian “push”, Microsoft will destroy them in the Smartphone field.
Why ? Well, the major problem appears to be that Symbian, need to resolve issues with its’ platform and menus changing between handsets. This leaves the business customer confused and probably in need of a training course to operate the phone! :) Whereas with MS handsets, the user interface is standardised and the OS functionality remains pretty constant throughout.
Read more here at vnunet.co.uk