Welcome to the Dis!
You'll find a lot of information about DVC on the DVC forums here. I'll be glad to give you my thoughts
We bought in a little over a year ago, after looking at it several times and not understanding how it would be worth it

We are a family of 4, always stay Deluxe and plan to keep coming to Disney every year at least once a year. After seeing the prices on the Deluxe resorts going up every year and seeing how much the buy in for DVC was going up we decided to "rent points" and see how we liked the villas. We checked into SSR (Saratoga Springs Resort) on a Sunday afternoon, went on the DVC tour and played with the numbers a lot with our guide. No pressure at all, we took the information back to our room and DH (the math/excell spreadsheet genius

) kept playing with the numbers and by Wednesday we went back and signed on the dotted lines
We have a DD14 (now) and DS 11, they will not share a bed and teenage girls take up a lot of space and time in the bathroom

We decided that we wanted/needed at least a 1BR for a week plus enough points to trade out for a value II week somewhere. I never thought that I'd want a kitchen & laundry on vacation, but I've found that I really do like having it. I still don't cook on vacation (some do and save a lot of money on food) I like have the fridge for drinks & leftovers. The washer/dryer in the room is great because I don't have to pack as much and I come home with clean clothes instead of a big pile of dirty laundry. It's easy to throw a load in at night and toss it in the dryer in the morning when we leave for the day. We've gotten very spoiled and have decided we really like the 2BR villas. The kids each get a queen bed, a tv, their own bathroom. We get a private Mater BR, jacuzzi tub and our own bathroom. The living room doesn't have to get taken apart and put back together each day, there's plent of room and everyone has "space"
DVC is not an "investment" , it is a pre-paid vacation for the next 40+ years. Once our loan is paid off, all we will be paying for is our dues, food & tickets. It also forces us to take the time to vacation & relax.
To answer your questions, yes there are perks/discounts for being a Disney stockholder but I don't know what they are. Yes, if you use your Disney Visa for your down payment you'll earn reward points and from what I understand you can use the rewards points to pay your dues.
DVC does revert back to Disney ownership after a set time (depends on the resort), however, they just added a 15 year extension offer (for extra $ of course) to OKW. It's possible that may happen with other resorts. Also, while some timeshares you own it forever, you may not want to when you see what it looks like after 20 years. Disney has a vested interest in making sure that the properties are well maintained.
DVC ownership is best for families who want to lock in their vacation cost, stay deluxe or at least at a moderate, travel to Disney at least every other year and plan to continue doing so. If you're happy staying at a Value resort, then DVC may not be as cost effective.
Hope this helps a little

Come over to the DVC forums
http://www.disboards.com/forumdisplay.php?f=7 --Operations, Planning & Mousellaneous & Rent/Trade for lots of information
