I'm a programmer, and for me 3DWS and UU3D is a must to have, since using Blender takes ages to get anything done, especially when I only need placeholder and test models, and for my own projects the 3DWS models are more than good. And I'm not going to pay $5000 for 3DSMax or Maya, artists have to do that though.
3DWS is old, and hasn't gotten any updates since years, but it still is the only tool to create exterior and interior buildings easily and efficiently. Maybe with a little practice you could get a similar easyness with Blender, but I don't have time accept Blender's non-CSG orientation (it does nice boolean ops (much nicer than 3DSMax), but it's not meant to do that). 3DWS is just the tool which does exactly what I want, and I don't care how old it is, it's worth the money.
You can even speed up your art creation time by creating a "draft" in 3DWS first, and then adding some details in Blender. Especially when creating huge building complexes this effect comes into play.