A personal bother is this. I recently bought an iPhone 4 as a replacement for my very basic cellphone. I would like to use one of the rangefinding apps while I'm playing golf. I really don't want to spend another $300 for a more-primitive dedicated GPS/rangefinder unit.
While it is less feature laden than your iPhone, my Approach G5 is certainly not primitive. And the fact that it's weatherproof makes it quite appropriate for an outdoor sport like golf.
I guess I don't see the difference between buying a new $400 driver each year, or buying a $300 device one time which will give me all I need for years to come. Half the people who post on this forum spend more than $300 a year just replacing gear that doesn't even need replacing, yet they agonize over spending that amount on a rangefinding device. To each his own, I guess.