You can count me as someone who has been 99% satisfied with the Blackberry 10 OS for the past four years. I have tried several Android phones, with the latest being a Lollipop one, and I've been forced to use iPhones a few times, which I utterly deplore.
I will be buying a KEYone shortly after launch (I'll wait for one or two monthly updates to work out the kinks.) I'm excited about both the hardware and Android N, but the real test will come after I have the phone. What's always happened in the past is that, after trying an Android phone for a couple of weeks, and getting it all configured and working, I run into a very busy period, with lots of air travel and mobile work, and I jump back to my Blackberry Passport because it just lets me work faster and more accurately. Part of that is the keyboard, and part is my preference for all the functions that are fully integrated into the BB10 OS. Most of my work is pure communications and Internet work, so I don't use many third party apps.
I suspect that it will come down to whether or not Office 365, including Skype for Business, works well on Android. I've tried the apps on my iPad, and was far from impressed. I don't have these apps on my BB10 phone, so the thought is that, if I can use them, that will be a win for Android. I'm not much of a Google apps person, so better access to those tools is of only limited value.
The KEYone looks like the absolute perfect phone for me from a hardware perspective. I love the form factor and the keyboard, especially the ability to create so many shortcuts!. I hope and expect that Android N is far superior to Lollipop and that I can make the adjustment this time.