I fly Dash 8 200 and 300s and we use it on every take-off while accelerating and getting the flaps up (Company SOP.) It doesn't have to be used in conjunction with the autopilot, we use it to adjust the flight director command bars when hand flying. So we take-off with flight director HDG and GA (Go Around, provides a 12 or 9 deg pitch up command depending on type). We rotate to the pitch bar and get the gear up, once we've accelerated to V2+10 to 20 we get the PM to set IAS which has the pitch bar commanding the IAS at the time the button was pushed. Climbing through 400' we select flap 0 and hold the TCS button while lowering the nose slightly to accelerate to the desired climb speed. The pitch bar will stick to the actual aircraft pitch until the TCS button is released at which time it commands the IAS achieved at the time the button was released. The autopilot can only be engaged after climbing through 1000' (aircraft limitation) at which time any IAS changes are made using the pitch wheel on the flight guidance controller.