My BB Bold 9900 was...
...replaced with a Lumia 630 when our IT department switched last year.
My first experience with WinPhone, it was a very positive surprise.
Going from the premium build quality of the 9900 to one of the cheaper Lumias was not a problem. The beating my phones sometimes get, the cheap looking, but extremely robust, Lumia 630 was actually a better fit for me.
Something about the UI appeals to me, and it ticks all my work features.
The built in calendar app is crap, but Chronos+ solves that, and is better than even Android's great Business Calendar 2 for displaying my schedule.
The app gap is substantial, and will be a deal breaker for many. But with mSecure and Simon Tatham's Puzzle Collection recently making their appearances, I'm covered and could easily make the switch from Android.