They're much too slow. It's understandable that it takes time to get the first version (WP 7) out of the gates, but from then on ... much too slow. There's no excuse. They should've replaced the project lead a couple of years ago.

Then, they have massive issues with their store. This is not acceptable as it's a piece of diligent work which a company like Microsoft just have to get done.

However, it's not over yet. I'm at a 600'000 employees cooperation and they strive to Windows Phone and Win 10 tablets.