Just to add my 2 cents, there has been a lot of mention of how everything works better on Android and iOS, but I found that to be not completely true. I commute a large distance everyday for work and what I found frustrating with Android ( and iOS to a lesser extent) is the ability of either OS to handle texting over bluetooth. With Cortana, texts were read aloud and you could respond. Not so with Android and everything I researched shows there is no solution (maybe you guys have found something, but the apps do not replace Cortana's ability).
Second, I hate the fact, with my Band 2 I have lost sms notifications and with that loss, the ability to respond to sms. Now my Band 2 is just a fitness tracker. This may be a marshmallow thing, as this used to function on Lollipop.
The last issue I have found is with the Android Outlook App, it is buggy, especially with the Calendar. By default, my calendar stays unchecked and if I enable it, the app unchecks itself, which has caused me to miss some crucial appointments. In order to get around this, I have had to switch to gmail app and turn off 2 factor authentication to get the gmail app to connect with my outlook account. I am sure with further research, I may be able to figure out the security issue.
The issues mentioned above were not experienced on my lumia 920 with W10M. Only reason I moved to an Android device was the lack of a good midrange Windows phone now that MS had discontinued support for my lumia 920. Now if any of you have any solutions to the above issues, I would love to hear about it.