You are right that the VIP does not out weight the great price of a resale, However there are some advantages such as being able to reserve the 4 bedroom pres suite at bonnet creek. If your traveling with a huge amount of people you may need the extra months to reserve this type of room. Because from what I'm hearing the pres suites are hard to come by. Also if it is your thing to have a specific bedroom such as one that faces the lake, or a bedroom in tower 3, so you can see the fireworks from epicot then this is something you can do with VIP. Without VIP you can't get specific rooms you have to take what they give you.
However I just don't see these little perks costing me an xtra 10,000-20,000 dollars. A wyn/ff salesperson may try to say that with VIP program you receive unlimited house keeping credits but your still getting hosed in that deal because your paying more in maintanance fees.