one observation, you were using it in dual mode and then edge. do you know if you were getting 3.5g with dual mode or if you dropped down to edge in dual mode?

i do admit for edge it's fast. and thanks to robby for that article, it was one i couldn't find again on the reception test.

an overlooked advantage of having a good antenna and no metal casing etc to turn the signal into heat is that you save battery
bad signal cause's your phone to boast the power to the antenna. if there isn't any loss through heat your saving on battery. also where other phones would drop to 2g you can still get 3g.

Edit:
for a test. get a gs2 if you can, and go somewhere that the reception is bad so the signal drops from 3g to 2g. then put the sim from the gs2 into the n9 and go to the same place. try get the same spot and hold the phone the same.
not an exact science but will give you an idea of the signal quality and if there's many differences.

also try speed tests in high with speedtest.net in high signal area's and low signal area's same sim.

the gs2 has good hardware in it so it's a fair test.