In all honesty, Mark099, you're talking to a pretty captive audience of
DVC members here. So you're not going to get TOO many complaints.
There have been a lot of threads in the past with great lists of pros and cons. Feel free to try the search function and you're likely to get more comprehensive lists.
Off the top of my head, here are a few reasons why DVC might not work for you:
1. Only want to use it for occasional trips to WDW, Vero or Hilton Head. While DVC does allow members to use their points to trade into other hotels and timeshares, it's not the best use of your points. If you like to travel, but only plan on making it to Orlando every 3-4 years, consider another point-based timeshare program. Most have lower Annual Fees (Maintenance) than DVC, thus reducing your recurring costs.
2. DVC doesn't always work well for those who travel on short notice. In order to have the best shot at a room at your Home resort, you need to book more than 7 months in advance. After 7 months, ANY DVC MEMBER can book at any resort, making it much harder to come by a room at some resorts.
The one big fallacy that may have come out of your sales presentation is the belief that you can easily book at any DVC resort. While it's true that you have access to all of the resorts, some of the smaller ones (Beach Club, Wilderness Lodge) have a very small number of rooms and thus can be difficult to book. There are also specific room types at other resorts that can be hard to get (any Standard View at the Boardwalk, Grand Villas at Old Key West.)
3. The point costs for a room on Friday and Saturday night are often two times (or more) the cost of a Sunday - Thursday stay. Thus DVC doesn't always work well for those who live near WDW and like to take quick weekend trips.
4. In most cases, don't kid yourself into thinking that DVC will actually save you any money. Our family is now taking better (and more frequent) trips than we would have been able or willing to do by paying cash. But that means we're spending more on transportation, park passes, souvenirs, etc. DVC should help improve the quality and quantity of your vacations, but it may not help your wallet.
I'm probably forgetting some things, but those will give you something to think about. Generally speaking, most people will tell you that their biggest DVC regret is not buying sooner. A decade ago points were selling for about half of the current cost, and many members received free park passes through the '90s.
But that's water under the bridge. If you run the numbers, you'll probably find that your DVC investment will pay for itself in 10 years or less. From then on, you get another 40 years worth of vacations (assuming you buy into Saratoga Springs) for a fraction of the cost.
Good luck, and don't be afraid to ask questions.