The report has harsh word for both BlackBerry 10 and Windows Phone 8. About BlackBerry 10, it reports:
"The operating system is hampered by inconsistencies, unexpected behaviors, and user experience friction that make it frustrating to use."
It's even harder on Windows Phone 8:
"Windows Phone 8 is a strange mixture of slick, original design -- and a surprising disregard for key usability, not to mention the lacker of some key user experience features such as customization options, pervasive notifications, or quick access to key settings...Windows Phone 8 is not very competitive in terms of overall user experience."
So there you have it. When it comes to productivity, this report says, iOS 7 rules the roost, while Windows Phone 8 doesn't even rise to the level of an also-ran.
If you'd like to read the full report yourself, get it for free here.