I've been using MC for work-related stuff - mostly textures and demo videos. Last night I decided to look at some of my photo collection. I was taking RAW images on my honeymoon last year, making NEF format files. To my surprise, MC displayed all the NEF files just fine! Even more, I could edit them within MC.
MC is nicer to use than NikonView, for sure. I'd like to make a couple suggestions:
1. With such large files, thumbnails take a long time to generate on an as-needed basis. It would be nice to have a background thread preparing off-screen thumbnails within the current selection.
2. When saving a file from the editor, it would be helpful to have a list of the available file formats, rather than needing to know to use BMP or JPG.
3. Support for PNG output format from the editor would be great.
4. A "Convert format" variant for images would be useful; in this case, NEF->BMP as a batch operation.