Hiya Showme. If you wander around the SW, Anacostia, even some areas in the shadow of the Capitol, there are sections where poverty and crime are endemic. Yes, G-town, Penn, and much of NW are nice, but income and wealth are very uneven in the city. And it is interesting--the Anacostia remains filthy, yet the Potomac, Rock Creek and others water ways in more affluent areas were cleaned long ago. The city hasn't even made a serious effort to prevent the discharge of raw sewage into the Anacostia when we have heavy rain, resulting in overflow from our woefully outdated sewage system.
So yes, it is a nice city, but I would encourage anyone to not lose sight of its dirty underbelly.