I have both of these. The quantum is a far superior product/build quality but you will have to add an outlet box to the side of it and wire that up whereas the Grozone is ready to go (and available at hydro stores). Both have features that allow you to set a temp where the fan will come on full speed and also a setback so the fan can run at a % of full speed when lights are off/etc...
just what you need, fer sure. They work very well, IMO....