Well, trueSpace 3.2 is free. And trueSpace 6.6 is actually fairly easy to use. You're not forced to work with a triangulated mesh and from at least 5.x (possibly a later version of 4.x) it has an add edge tool which makes it simple to triangulate faces with 4 or more sides exactly how you want.
Somewhere in there they also added an Add Face tool that automatically highlights any area with no face, with a continuous line of edges bounding it, that's under the mouse pointer. Click and there's a face you can fix up by adding new edge across it.
Combined with the Delete Face tool, it's very useful for fixing backwards normals. Delete the face then add it back and it checks the normals of the faces around the new hole and aligns the new face to match.
Another nice thing about not having to fully triangulate a model (until you pof it) is it makes UV mapping easier.