Hi Everyone,
I bought my Galaxy Nexus in early April from Costco. My device came with 4.0.2. I have to say that my stock experience was similar to some of the stories posted here. My phone never died in two hours on battery, though. I've always gotten at least 5 hours out of it. I CAN verify that I did experience the 3G/4G switching issue. I'm in the LA/Orange County area, so 4G coverage is abundant. However, compared to my wife's iPhone, my signal strength was laughable.
I have since rooted and installed the latest Bugless Beast ROM + the 4.0.4 radios. The difference is night and day from a reception stand point. Switching from 3G to 4G is instant! I just moved office locations at work and upstairs I get 4G, but my office is in the basement level and I only get 3G down there. So I watch the transition happen every day. Everything is better on 4.0.4! All I can say is before you give up on your GNex, try the new ROM and radios. I almost returned mine because of the issues I was experiencing. I wanted to love it, but I couldn't excuse the problems. Rooting solved my problem. Do it...today!