Retrofitting Underfloor Heating with Suspended Timber FloorsCost would be fairly comparable, depending on floor finishes Polishing concrete can be expensive but so can polished hardwood floor's Tiles are cold because of no heating from sun or underfloor heating Do costing's first as Hydronic in a slab will make it expensive when compared to a timber floor on pier's, bearer's and joist's Suspended floors can be either concrete beam and block or timber, but I can think of any advantages of using timber other than for DIY and easy to lift/move materials With a suspended floor you would have a concrete oversite (slab) over the ground beneath the floor or you could lay a ground sheet and gravel
Farm Structures Ch5 Elements Of Construction Floors Roofs