Ok, there are a few things that you get as a perk with developer points that you don't get with resale.
1. Club Pass. This is if you want to book a WorldMark resort. The fee is $99 per reservation.
2. VIP IF you have 400K points or more. <--VIP benefits can change at any time and they do change. VIP is three levels: 400K Silver, 700K Gold and 1M Platinum.
a. VIPs get a newspaper at the resort.
b. They CAN put in for an upgrade in room size. This has been working for some and not for others with the new website.
c. They can book at a discount of 25% - 50% depending on their VIP level (this is at the 30-60 day mark, I believe)
d. Unlimited Housekeeping. (Gold and Plat...I don't know about Silver) The rest of us get 1 Housekeeping credit for every 1K points we own per year. If you run out of Housekeeping, you pay $2 and change for each credit. If you take short trips in large units, you might run out.
e. Unlimited reservations (All VIP or just Gold and Plat?) The rest of us get 1 reservation for every 77K points we own per year. If you run out, you pay $19 online or $29 (?) via phone.
f. Extra guest certificates. Everyone gets 1 guest certificate per year. I can't remember how they are doled out, but I get 2. If you need more it is $99.
VIPS can get an Advanced Reservation Priority at another resort and that makes booking a hard-to-get resort easier.
Everyone has Advanced Reservation Priority where they own...this lets you book 10-13 months ahead. At 10 months, points are points and you can book anywhere. Some of the Presidential Reserve units are saved for PR members and then there is Margaritaville (you are supposed to have to own there to book there, but there are plenty of people who are getting reservations).
If you think that the discounts and upgrades are worth it, go for it. I figured it out that it would take 30-40 years to recoup the cost. I am careful to not use up my Housekeeping and reservations to avoid the fees...but honestly, my 154K points from resale cost $700 and the same size package from Wyndham was $22,000. I think that I can pay some HK and reservation fees or spend more points for a unit for the $21+K that I saved by buying resale.