2nd is always my favorite. 1st maxes out early, so I spend most of my acceleration in 2nd. 3rd is pretty good too.
Now, does our boost ever hit in 1st? It never really feels like it under acceleration, so I figured that in 1st our engine is only outputting about 180hp and similar torque. So we aren't making max HP and torque until the boost kicks in for 2nd gear.