We are starting to think about purchasing DVC points...
Are there any disadvantages to buying VB and being able to use the points at WDW reorts??
There is a lot of great information on these boards and if you're looking to buy it would probably be a good idea to read as many threads as you possibly can. Regarding Vero Beach specifically, it is a very, um, difficult resort to own. Typically the people who own there tend to stay there. The maintenance fees are significantly higher than any other DVC property due to their oceanfront location. They are high to the point where they are rapidly approaching the price at which you could rent points without the initial buy in. Any initial savings you could realize by buying VB over a more expensive resort would be quickly eroded away by the higher maintenance fees. Resale prices at VB are very, very low, as is the demand. So if you ever needed to get rid of your contract it could be difficult. There has also been speculation that if Disney ever were to spin off a few of its locations and remove them from the DVC system, it would be VB and HHI. Probably won't happen, but do you want to worry about it?
Finally, to add to what the previous posters mentioned, there is a chance that you could be completely shut out at the 7 month window, thus making it impossible to stay anywhere on property. It's probably unlikely, but at the busier times of the year it could definitely happen.
The general advice given to new purchasers is to buy where you want to stay. I've also seen people advising new purchasers to buy at a place you wouldn't mind staying at, in case you couldn't book at your first choice. Through your research you will find that certain locations (such as AKV value rooms, AKV concierge rooms, most everything BLT and BCV) almost always book prior to the 7 month non home resort booking window.
My advice is to read, read, read, and then take opinions like mine and the others and decide what you agree with and what you don't. You might even decide after doing your research that DVC is not the best option for your family (although with 4 kids I'm guessing that you really want to start staying in 2BR villas).
Best of luck in making your decision!