With 2 phones every time I need to do something I have to make a decision which pocket to reach into. Here is how I have now worked out how to make the decision:
If I need something in an instant
If its the location of a restaurant or a google search to settle a debate I pull out my iPhone. The browser is much more spritely and maps gets my location way faster and more accurately (probably thanks to
www.skyhookwireless.com technology)
If I want to know whats going on
A quick swipe and I have Facebook, foursquare, and twitter on my homescreens so I can stay up to date much faster than launching at least 3 apps on the iPhone. Also the notification bar lets me know all the updates inside the rest of the apps from SMS, to chat, to email so I use the Droid to keep up with friends and communication.
If I want to be entertained
Just the brand idea of going to my iTunes vs music makes me pull out my iPhone and the richness of the application design makes me feel like I am being entertained rather than using a Microsoft windows application on the Droid. Games on the iPhone are 400% better than the Droid. I have the paid version of Bejeweled on both phones, the speed and graphics on the iPhone give me that true play experience rather than feeling like I am clicking controls on the Droid.
If I want to consume information
The screen on the Droid as most people have said is fantastic being able to see full webpages in landscape is amazing. I now find myself finding stories on the iPhone then emailing myself the link to actually read on the Droid. I can't wait for the Kindle application to come out on the Droid as to me that will really feel like pages in a book rather than the flash card experience I have on the iPhone. Also I can now go to meetings with the PDF on my Droid and save a tree (as laptops always get in the way of a good meeting).