I use the Domain Wizard all the time. Very easy to use, and greatly simplifies life. The only improvements I would like to see would be more distinct state lines to make setting up nests easier.
I also will sometimes use the WRF Portal to generate the first namelist.input file if I am starting on a new project. But after that I just update using a text editor.
Have not tried running any of the code within the portal.
All-in-all, a very valuable program!