Snapseed opens the Nikon RAW files without any problems. Edits are easy, see my last post for a brief 'how to' on editing. The nice thing about this workflow is that once I have imported my files to my iPad, I can choose one of two options. I can delete the files off my SD and CF cards, so I can shoot more images to them, or I can, and did, keep the files on my cards so I can have a backup of my images while I'm away from my computer.
Once I've finished editing a file I have the choice of saving the file, which saves the image to a separate file than my original. This is nice because I don't have to worry about overwriting the original file. I can also email the edited file, or share it on Facebook or Flickr. You can see some of the images that I've edited here: http://web.stagram.com/n/rlwall/