Thank Michael, thats great news, In my opinion RealDWG is the way to go...

Hi Moe and thanks, to add Microstation is built upon the 'Parasolids' solids modeling toolkit; as such, it is always better to export in a "solids based" file format (such as Parasolids .x_t, ACIS .sat or STEP)

Autodesk also recommends ACIS SAT for Autocad, Revit, etc.
AutoCAD is based on the ACIS solids modeling kernel, so the ACIS .sat file format is a natural choice for exporting solids-based data with no loss in quality