@CrackedBarry
Let me tell you what I think,
Regarding controlling an app via phone to tablet, Bridge will allow everything to be controlled not just on a per app basis, its global. Plus the Open On feature is better than IOS since you don't have to start watching a movie on say an iPad then press a button to start airplay. Open on pushes the media to the right device at the start. It isn't mirroring.
You can't use your IOS device or Android phone to type on another device (tablet) without an app that controls just the app it was designed for. RIM wins here because you will be able to use the phone as a remote for every app. Thats fully baked into the OS!
Better integration between devices, or More devices?
Controlling household robots? Well if the roomba was QNX based it might be nice

Aside from vacuums, having an advantage doesn't suddenly create a disadvantage. Options are good yes? As far as niche markets go, isn't that why there are so many apps and in many different categories?
Reboots a thing of the past, we'll see. But yes not an advantage as others have said. I will point out that you neglected to include Tablet OS along with Android and IOS as having that ability.
QNX wasn't designed for what RIM is using it for. Since it was created before people had mobile phones?$#@! Fact is as an OS QNX does what it does well enough that extremely large companies use and depend on it for the most critical of jobs on Earth or above it. What RIM does with it is put it in the hands of ordinary people. QNX doesn't need to apologize to you for being awesome. Yes time WILL tell...
Further to what the OP stated about the separation of OS and user data, Linux and I'm not sure about QNX as a default gives users a home partition which is separate from the OS. You can format the OS partition and install a different one while keeping all your data aside from any OS modifications obviously. PB only offers wipe OS which I'm pretty sure formats the entire "disc". Its one of my favorite things since I know what files I've changed...I'd like to see the same w/QNX - a home/user partition.