I am a big fan of PhotoShelter and have been using it for over a year now.
I use the lightbox to get images to clients and I store all my raw files (currently 14,577 of them) there. PhotoShelter also blends in seamlessly with my Flash-based website:
www.manginphotography.comHere are some of my favorite things about PhotoShelter:
1) Local and Geographic Redundancy
2) Able to read raw files
3) Blends seamlessly into my website
4) Collaborative lightbox feature is great for communication with editors
5) Export to FTP servers directly from PhotoShelter means super fast uploads
6) Export from Photo Mechanic and Apple's Aperture ties in directly with my existing workflow
No ther existing service out there today can do all of these things- therefore PhotoShelter is perfect for me and my needs.
Best of luck with your decision.