If that is a transducer element and you are going to build the electronics yourself, the Q factor depends on how your electronics interact with the sensor.
Is that a transducer element, or a fully working commercial sensor?
EDIT: The "Best Oparating Frequency" is +/- 4%. That is not in any way related to sensing accuracy or resolution.
EDIT2: Sorry, I was wrong about the Q factor. Of course mechanical resonators also have a Q factor. But, attached electronics do affect the whole systems Q factor. Smaller Q factor means broader bandwidth and less ringing. So actually broad bandwidth might actually be better than narrow. But, small Q means usually less sensitivity at the resonant frequency.
Can you post a link to full datasheet of that transducer?