There's a big difference in Timeshares. You have companies such as Disney, Marriott, Hilton, Hyatt, all 1st class timeshares.
Then you have mostly everybody else who range from absolutely terrible to good or even very good, but not quite in the same caliber as those listed above.
There are numerous timeshares in the WDW surrounding area, but I would consider only a handful of them comparable to DVC, such as the Hilton. The main difference is where they're not actually at Disney, they make up for it by being first class resorts.
We own Marriott and are very happy with it. One advantage to that is we are members of Interval International, and can take advantage of their getaway programs. While Disney trades through II, DVC owners are not directly members of II.