It does have a lot of missing features compared to blender, and development has been very slow since Bjorng left the project, but it is really the most intuitive modeler I know.
It does one thing and one thing well. It's still my favorite box modeling application. I can get a character modeled up 2 times as fast as Blender. I'm a big fan of Blender and use it for character animation, but my familiarity with Wing 3D goes back many many years. Back then Blender's modeling was horrible. These days Blender does everything, and most things very well!