Nothing wrong with the non-Cherry Hill options, all nice parks AFAIK, but the Cherry Hill has the best public transportation. From many of the others, you have to drive to METRO and get there early enough to fight the commuters for a parking space. The Virginia parks are all pretty good, and I'd recommend them for anyone visiting who plans on spending most of their time on the Virginia side of the Potomac, but if you're doing the typical Washington, DC monuments, museums & Mall touristy stuff, save yourself a lot of hassle and stay at Cherry Hill.
