I think that at distances up to 500Nm the economy is still on the turboprops side. Fuel burn - up to 50% less than in an RJ... Flight time? For a 500Nm sector the difference will be less then 30 minutes - not that much... Comfort? - a new ATR/Q400 isn't any worse than an old CRJ... I think the main problem is the passengers' perception. My outfit operates turboprops both on domestic flights (up to 300Nm) and some longer international routes. I noticed that although the pax seem to accept the "airplane with props", on domestic flights, they get disgruntled when they learn they're flying a turboprop abroad. Most of them really hate it. Therefore I think RJs should be used on anything longer than 250Nm - to improve company image, even at some expense of economy...