I've had the Galaxy Nexus since its release date in December, and I have no doubt that it's the best phone currently available. Ice Cream Sandwich is a huge improvement over Gingerbread - aesthetically, reliably, and performance wise: everything has been excellent! It's never crashed, lagged, or gone haywire.
As of right now, my Nexus has been on battery for 1 day & 13 hours and I still have 10% left. What do I do for awesome battery life? I use WiFi all the time. It automatically joins my work and home networks, where I spend most of my time. When the phone is connected via WiFi, it disables the 3g and LTE radio, which use a lot more power than the WiFi radio. The battery holds up so well, I don't even charge it at night.