Some people find that they're able to get more things done when they don't have the distraction of a smartphone in their lives.
But these days it probably doesn't matter what phone I use, as I leave the thing at home as often as I take it with me. Now I'm no longer on-call, via SMS, I just don't need the distraction.
Then I go into the kitchen at work and see people getting coffee while checking their email. wat.