if you are doing that kind of work, you might want a bluetooth gps receiver anyways. When the mogul screen goes off, the gps goes off as well. Some software programs can't recover from it, some can. But i find sometimes i have to reboot to start my gps up again. So keeping your gps running and your screen on the whole time will kill your battery life on your phone rapidly. It drains quickly.
Bottomline, unless you have a power supply right where you're at in the field, bluetooth gps is better.
The external one i use is this one.
http://www.buygpsnow.com/Product/Glo...unt)__925.aspx
It has a 20 hour battery life and is waas enabled.
From all the datasheets and stuff about the mogul's chipset, nowhere does it mention Waas or Egnos, safe to say it doesn't utilize them. If it did have it, then their marketing people would suck for not putting that out there.