Previous iPhone 4 and 4S owner. Now a galaxy nexus owner. The GN is by and far the best smartphone I've ever owned. A few areas of the iPhone have it beat (camera and storage size comes to mind) but everything else the GN is superior (mail, browser, keyboard, notifications, battery life, hspa+ speeds, etc.). I assume my experience will be in the minority here though.
Consider me a convert but I'm still watching closely at what Apple will bring to the table with iOS 6.
I'm surprised you listed Mail, that's actually one of the things keeping me away from Android:
It simply does not handle email threading very well, or at all. On the left is the iPhone mail app, the relevant emails are grouped together. The middle is the Droid Bionic, it tries to do the same, but misses some. The right is the Galaxy Nexus, where everything is in one flat list.
Whenever a co-worker shows me a new Android phone they just got, that's the first thing I look for, and it still works that way, no matter which client they are using.
Is this an issue on your Nexus as well?