The Dash 8 D's caught quite a few of us out when they first came into service, the climb rate is that of a jet.
A similar thread but with Jets saying why do you vector Turboprops ahead of us happened a few months ago when i took some stick because i did just that. When you work turboprops on a daily basis you are well aware that in the last stages of the approach they can maintain a higher speed on final than jets, they can also slow back very quickly as well. ATR42s are capable of holding 240kts to 4 dme if required and can bring the speed back very quickly.
How the traffic gets presented to us though can make the difference to how the final sequence is established.