Majority of BB10 users who switched to Android will tell you BB10 truly was a superior OS (apart fro the app gap), Its a travesty BB10 never took off and was late to the party.
the BB10 was far more "fluid" and stable, and the multitasking blows android out of the water.
Example : I use youtube to stream my music. On BB10, I could play youtube, and "close" the app while the music still played, and continue doing other tasks or consult my GPS. On Android, as soon as you exit the youtube app to respond to an email or check a website or check your GPS, the Music stops. Stoooooo-pid. (yes, I know about "split screen" on android, but its still ghey and doesn't work with all apps) and on BB10, I could open and use as many screens as I want and switch between them seamlessly.
Also, on BB10, when I would stream my youtube, I would "close the screen" to save battery life. ON Android, as soon as you close your screen, the Music stops! Of course leaving the screen on chews battery life. Stooooo-pid.
For any BB10 ppl who are switching over to Android, do yourself a favour and get a BlackBerry Android, they did their best to bring the BlackBerry experience, security and flavour over to the inferior Android framework, so you will still be familiar with it. The Hub works just great on BB Android.