IMHO,
DVC is great for stays at WDW if you want more space, very nice accommodations, and would really not be satisfied staying offsite.
I personally would not buy DVC (even resale) unless I intended to use my points almost exclusively for stays at a DVC resort
at WDW.
Non-DVC points uses are almost always not good value, and in those four locations where DVC has resorts away from WDW (CA, HI, VB, and HHI) there are other options that are probably better. That's a personal opinion and there are those who disagree.
Yes, you can exchange out through RCI, but only for a small fraction of the total RCI resorts (<600 out of >4,000), and the process is very uncertain. For most systems (not just DVC), exchanging is not a great option unless you spend a lot of time learning how exchanges work and are willing to really work at it.
If your other choices of vacation destinations are Washington DC, Pennsylvania, and Wisconsin, I would take a long, hard look at Wyndham. Wyndham contracts can be bought on eBay for very little (sometimes $1 with free closing, but usually for only a few hundred dollars).
Wyndham has a total of about 84 resorts currently, including two in the immediate DC area, several in the Poconos, several in the Wisconsin Dells area, 11 in Hawaii, and five in the WDW area.
Go to
www.wyndhamvacationresorts.com and click on the "Explore Our Resorts" button, That will give you a map, and then you can click on a state and bring up all of the resorts in that state. Ignore the "affiliate" and "associate" resorts, because with the exception of the Mexican affiliates, you won't have much luck trying to get a reservation.
Hilton and Marriott are also fine systems, with a LOT of very nice resorts, so those merit a look as well. And there are others.
TUG (the Timeshare Users Group) is the best place to research any non-DVC timeshare.