I own at the Occidental Aruba. I believe the difference is supreme units are slightly larger and ocean front. The deluxe are ocean view and basically the size of two Occidental hotel rooms. The deluxe have a king bed, 2 bathrooms, a queen sleeper sofa, kitchen and dining area. Total privacy for 4 adults. I really can't tell you anymore about the supreme.
I also read your other post regarding purchasing resale. That's exactly what I did. All the resort did was transfer the contract into the new owners names and we are bound by the old owners terms (therfore my contract does not require the all-inclusive be purchased).
We have traded to other properties..last year w/ Aruba closed for most of the year for renovations we traded to Royal Hideaway in Playacar, Mexico. The unit trades as a 2 bedroom therfore we got 2 rooms at the Royal Hideaway. We do have to purchase the all-inclusive at other properties, but for anyone that has been to the Royal Hideaway, you know it's hard to beat for food and service so it was well worth it.
BTW check out this website for Occidental Aruba owners....