I was going to try the traffic service but haven't due to all those issues mentioned above.
Originally Posted by
runningshoes
...My current unit (Garmin 255) does well on highways but struggles in bigger cities like NYC, Chicago, and DC with reception and timeliness....
In poor reception area, you need a unit with dead reckoning function. I have a Garmin Streetpilot 2650 along with two factory installed GPS that have this function.
Basically the GPS has a gyroscope to detect direction change and get vehicle speed and forward/backward signals from the car. It then plots the estimated course until the GPS receiver gets good satellite signals again.
http://www.roadmapgps.com/glossary/dead-reckoning.shtml