I'm also a long term owner (since 1999) and seen the service, quality and perks on a steep decline as maintenance fees rise (manageable for now, but no real value returned IMHO), basically if you do buy you should consider the only guranteed advatage you will have is Large Deluxe Living Spaces w/Kitchens/Laundry (Makes long trips with many family/friends possible and comfortable, and maybe more economical if you eat in).
When I bought it was down right magical (as it should be) upkeep was immaculate and your were treated as a world class citizen and perked up big time (tickets, valet parking, golf, pool hoping, discounts,exclusive stuff etc...), most of the perks have been eliminated, restricted or scaled back to where they are a joke for the most part, for example the cruise points are outrageous now when they used to be a good deal. And overall the maintenance/upkeep of the resorts even the new ones, is back on par with your average hotel, I will admit this upkeep problem also extends to the parks and other facilities.
With the early good years I belive I have gotten a good return on my investment, overall, however, there is no way I would do it at the prices they have set today and even resales would be a big if for me. In fact I have taken trips outside points to deluxe resorts using the advertised discounts got free dining, upgraded deluxe rooms, tickets for less than my annual dues bill.
It's just a shame to see them cost cut and remove magic over the years!