I don't know what this last reviewer is on about? I use ViaCAD almost everyday. Yes it does crash from time to time- about once a month actually- but no where near rendering it 'useless'.

If you are looking for a more cost effective alternative to Solidworks, on Mac OS X too, this is the place to start. ViaCAD will even talk with Autocad and Pro Engineer and will now sucessfully output OBJ files, which are useful for more generic modelling apps such as 3DS Max. It is worth also mentioning that ViaCAD uses the same Spatial kernel used in many of those PC-only apps. At $99 you can't really go wrong, but you'll probably want the parametric constraints that VC's big sister Shark FX has got. However, where it stands, ViaCAD V6 is already a powerful engineering quality technical modelling system, and is in my opinion, worth every penny.