I don't think it is the network. My father's Amaze does not have this problem in the same places.
ILWT has been the most reliable ROM for me so far. I am currently running Andromadus b4 and am considering switching back because of the data drop-out issue. I have tried 5 different radio versions now.
It must be the ROM. Perhaps it encounters some data it can't make sense of and crashes. Perhaps it just needs to restart itself when this happens. A simple mobile data off, mobile data on fixes it almost every time.
I also find the bars reading incorrect. I be driving down the road with my screen on and the charger plugged in, and it will show me full bars. I can pull over and park for a few minutes, bars still full. Then suddenly half bars, no bars. This behavior is from a device that isn't being physically surrounded / shielded and is stationary.
Anyways, my G2 is getting old and it needs a another core to keep up with the way I now use it. I will wait for Jelly Bean but will likely switch to IOS.
Reasons If You Care
The menu button disaster is a big one for me. Also the lack of quick updates from Google for Nexus S and Nexus One. These devices should have had OS updates released on the same day the Galaxy Nexus was released.
ICS should have been backwards compatible for older devices as well. A few #ifdef in the code for fancy screen rendering and such. Big, huge fail!
Google, also, should have required no physical menu button for access to Google apps to enforce the new way. With only like 7% ICS market share no wonder app devs write for GB.
Google's handling of Android updates has opened my eyes.