Depends on what you will be utilising it for. The CRJ series is faster, and can do many flight cycles per day when it is flying more than 500 miles, but the Q400 and any turboprops have an advantage when the distance is less than that. Although, sometimes (depending on the route) the Q400 will also be faster than the CRJ series, as well as being much more fuel efficient.
One example I can possibly provide is that Virgin previously used to serve Townsville Airport with their own ATR series then to 20 year old leased Fokker 100 jets to fly to Cairns (approximately 350 km north, which equates to a 3.5-4hr drive by car, or 45 minutes flight time), but using a jet required much more fuel, and therefore costing passengers more money to fly to Cairns. They sadly pulled out of that route, and QantasLink is the only one to serve that route, and guess what with? It’s a Q400. The route sees up to 7 Q400’s flying that route daily. Although, I don’t know why people want to fly to Cairns via Townsville for around $120 when it’s cheaper to drive. lol
Using a turboprop on such short routes not only means low fares, but also means more profits for the airline as the plane doesn’t use much fuel. Operating route with a smaller 76 turboprop plane compared to a 100 seat jet airliner is pretty self explanatory, when it comes to profitability.
I can tell you this right now, Regional Express operates old Saab 340 props, but they are getting old. They want a turboprop that can succeed those planes, but also make it more profitable for the airline - as REX previously has had many mechanical failures with those aircraft, I think an engine fell off of one. (Goes to show the Aircraft is like the Automobiles they made previously 😂)
But to the point, they will probably need to look at another turboprop to replace their existing fleet of Saab’s. If they were looking at it now, it would be weighed up between the Dash 8 and the ATR series, but if it’s in future, there might be a whole lot of new technology to compensate.
End of story, it goes to show currently Turboprops are a most needed aircraft in the Aviation world today.