Currently the only difference between a SDN Script Writer and an OSD is the PIP (permission wise).
Getting the ranks:
1. The application for OSD is very vigorous, very selective, sort of a lengthy process, and only picks the best in the business.
2. SDN Scripters get their rank by submitting any working script on the SDN.
Their compensation as of now is exactly the same for both, essentially Lifetime Sponsor. Many members of the community are concerned with SDN Script Writers de-valuing their $10 payment. With that said, I feel the SDN Script Writer compensation presented above, is fair. SDN Script Writers also have the potential to earn the same amount of money that an OSD does.