I said MOST balanced - traders are OPed, and I say it one more time - THEY are OPed at any lvl. I was sepaking in most part about all other classes (except Shades) on that level range. You wont find such balance at any other level. Closest to it would be 200, as Kiceie said, because traders can be countered by vast toolsets that other proffesions have.
In duels, toe to toe, without predraining trader I have such results vs 4 different twinks (and skilled players: 1) 3:1 2) 2:0 3) 1:4 4) 3:1 - on Enfs and following results on NT: 1) 1:2 2) 1:3 )3:1 - so, as you see, results may vary depends on luck, reacions and tons of other stuff.
If trader lands both drains, every char is screwed, like Mako said. As it goes for other classes and duels betwean them, its still most balanced range. peroid.