As far as I can see, both Emerald and Flybe are planning four rotations a day on their Belfast-based aircraft (ATRs and Q4s). If flying short routes like Glasgow, both could probably go to five but look to have the common sense with all of the trouble out there on airports and ground handlers not to do so right now!
Apart from some false sense of confidence that pitching a Q4 against a jet on BHD-LHR is a good idea - which I don't think anyone with an ATR would - then I can't see any difference beyond the fact the Q4 is a lot heavier, burns more fuel and only carries six more passengers (if full - which I doubt anyone will be with competition on most routes).