W.r.t. one conf file vs. another, perhaps the phones are caching information w.r.t. the time servers or the suppliers of AGPS data. When the files are changed out, maybe the cached data gets invalidated and a slow GPS phone becomes fast again.
The issue with North GA vs. South GA, well, that might mean packets of data that are needed in the AGPS solution just aren't flowing through the same cell towers and internet hops from every location properly. Maybe that is a VMUSA networking issue.
This might explain why some people (presumably with the same GPS electronics and antenna) aren't reporting lock delays, and others are.
And then there are some people claiming with modding their libraries, they can now see more sats and get a GPS lock inside their house where they couldn't before.
And so to me, it seems like the "solution" is probably a combination of an optimized gps.conf file which specified the time servers and other important parameters, and better library files like those provided over in XDA forums that do a better job in processing the information from the sensor HW and the network...