I am mostly using Wings3D for my modeling. For me, I will mostly use Blender for two reasons- (1) certain modeling effects impossible to do in Wings3D, and (2) use for setting up certain rigging and animation effects (such as cloth simulation). I like Wings3D because it's simple and intuitive in making models. I have much more control without feeling like I'm making a big mess like I do when I use Blender. Then too, Blender is a do-everything 3D program.
Another thing of note... I've almost entirely stopped using SketchUp since I now think Wings3D is a finer program. I may probably use certain textures from SketchUp if I plan on making textures for certain objects.