There is nothing wrong with any part of PG or DC. If you live in or near a area where there is a lot of people there is going to be crime. I suggest you look into SE, brookland, providence, ledroit park areas of DC and you should be able to find something affordable. I am a product of DC and PG schooling and I am doing just fine. I now attend Howard University. You will have no problem with diversity in the metro area. I suggest DC so much because the district is in the process of trying to rid the city of blacks. We all should invest in our neighborhoods.
Anyway there are lots of deals in DC if you look and I wouldn't sleep on PG.