Mine has improved with miles. The shuddering seems to be gone. It still shifts hard occasionally, like a poorly executed manual shift, but that happens mainly when it's cold.
The absence of a torque converter is both a good and not so good thing. It's more efficient and it's more responsive if the revs are high enough. But the transmission shifts through the gears so quickly that sometimes, there's not much response because the revs are too low. A heavy foot and a downshift or 2 are required, or the trans. can be shifted into sport mode. This wouldn't be necessary with a traditional auto. trans because the torque converter would allow the revs to come up for more power in the higher gear.