my Q5 updated from 10.2.1out of the box to 10.3.1 with no further updates has been very solid for a year. My Passport on 10.3.0.908 was the worst and I still remember that. It ranked up there with Yosemite being horrible on my Mac mini.
i think for me stability has depended on the device, os version, and maybe update path/method and that goes for any manufacturer I've used.
idk if BB10 is the most stable but my Q5 has been better than my iOS devices on 9.1. My 3GS otoh might edge them out on iOS 6.1.6 aside from apps closing/crashing due to a lack of ram, it's been a rock.
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