In the last version of IFC manager I added an option(a bit experimental) to export extrusions for super simple geometry like a straight beam or floor slab. It does not work when there are cutouts.
Than you do get the best type of solids in IFC.
For example: Classify wall frame as an IfcElementAssembly, the beams as IfcBeam/IfcColumn or IfcMember, and inside the beam an object classified as IfcExtrudedAreaSolid.