iPhone GPS Affected by 3G Connection

According to iPhone Atlas, some users were getting strange and inaccurate GPS readings when on the 3G network with their iPhones (being in Oregon and being shown in Texas on the Maps application). However, the site also states that some users have noticed that turning off the 3G data connection and reverting back to EDGE helps to resolve the problem by showing the accurate GPS positioning.

It seems that 3G is the root of other problems for the new iPhone 3G as well. Some users have also noticed a slight echo when paired to certain car speaker systems while in 3G mode. Again, reverting to EDGE may help the situation.

I wonder if any Windows Mobile users are effected with the same issue, either in Google Maps or Live Search. If so, does this trick help? I've always had good location readings from my trusty Tilt.