I have a GNex. I did notice some connectivity issues, but after updating to 4.04 they went away. My girlfriend has a Verizon Thunderbolt and I constantly check hers every time I lose connectivity to see if mine is still having problems. I found maybe one time where she had signal and I didn't, leading me to believe that the issue is fixed.
Also, I did notice there is a lag time where the internet doesn't work whenever changing between wifi/3g/4g that I thought was a signal strength issue. I realized later that that's independent from the signal strength and just always happens. It's indicated by whether the signal bars are gray (connecting) or blue (connected)