For bad reception on your GSM Galaxy Nexus, you can fix easily by flashing different radios.
For example, I bought my GSM Galaxy Nexus from Europe which contained European radio. Due to that, I was getting very bad reception here in San Francisco, California. By swapping out my radio to a North American version, my reception problems disappeared where my data would disconnect at random times during the day.
I have these radios you can use for GSM Galaxy Nexus: