Which is the best? During the days when the iPhone was only available on AT&T I used the Blackberry and still miss some of its features, but overall the iPhone is superior. But these days the Blackberry has vastly improved and may actually be a better product over the Android and Windows Phone operating systems. So what do you say?
As others have already pointed out Blackberry OS as we know it is essentially dead.
What Blackberry however will do, is going forward, base all future products on their Android OS skin. That being said, Blackberry's hardware output is practically stagnant with the Priv being their sole hardware release in well over a year.
The Blackberry priv, was definitely a revision 1 android handset and not without it share of problems both software and hardware. But was a good starting step, but one that was priced too high to gain much traction and not readily available.
Blackberry as a hardware company has found that MANY European carriers and stores are now unwilling to carry Blackberry devices as they simply do not sell.
Windows 10 Mobile is pretty much a horse on its last legs. With Microsoft retiring many of its mobile staff and with sales of the recent devices failing both at retail and critically (never have windows phones receives such poor reviews as the 950/950XL). Windows 10 mobile is littered with stability and app issues. Continuum offers an interesting prospect, but its likely a solution to a problem that no one really has or wants.
Currently the only way anyone could possibly think Blackberry OS or Windows Phone is offering a better product is if they actually haven't used anything else and have blinkers set to stun.