I love unmodified android. I won't get an android device that another company has modified due to how long, if at all, they take to get updates. I also think they're kinda ugly or gimmicky anyways.
Nexus 5 and 7 I loved.
Nexus 9 is disappointing. It's just not powerful enough to provide a smooth experience for me.
Developing wise, I'm conflicted. I've done iOS and android development. I don't like Java and I like ios's framework pattern but android is easier to get up and running IMO which is nice. Also now that iOS has Swift, which I think is a lot better than objc, it makes it harder for me to want to develop for Android. I know you can develop in a bunch of different things for android, but if I was doing something for production, I'm not going to be using something not supported by Google.