So I bit the bullet this morning and installed Nova launcher (and prime) onto my 50. I've purchased it previously when I had my HTC and loved the customization of it. I've used it on 3 tablets afterwards as well.
I was able to set it up with the same look as the blackberry launcher with the exception of using swipe up for app tray. The performance feels quicker, and battery life seems like it's draining less. I've set it up exactly as I wanted it but setup took roughly 45 mins, and I've only used 2% battery drain. Not bad
Have been using Nova for a month. Have not noticed any battery improvement but like it enough to replace the BlackBerry Launcher. If you want to use popup widgets, intall the paid app Popup Widget from Playstore. It creates home screen shortcuts that pop up widgets. Not as elegant as the BB Launcher's, but has lots of customizations to keep you happy, including on screen adjustments to the size and the location of the popup window and multiple instances of the widget.
I had nova, bought it ages ago.
But now using Action launcher 3, I find it faster & more intuitive than nova. Plus I can get my dtek50's homescreen just the way I want.