Nikon has two non-specialty software packages
Nikon View
Nikon view requires a separate download. Then it required two more downloads and installs to bring it up to the current version. At no point was I able to get the transfer to work but I was able to see the folders on the memory card within the Nikon program. I kept getting a message that there was no memory card attached.
Picture Project
This worked as soon as I installed it. The interfaces is intuitive and attractive, it does its own updates, and it's quite responsive. Unfortunately it seems more limited than the Canon software. There's no ratings, photo-stitch, batch processing, or display of focus points. It requires paying money to remotely control the camera. It does support collections.
Ultimately because its imports create another copy it will have similar problems to Iphoto.
Bugs
Picture Project In touch which is used to share pictures told me it needed to download a module before it would work. Then after I told it to go ahead it said the module was not available.
I have version 1.5 there are 1.51 and 1.52 updaters. When I did Check for Updates (which would have been better off under the PictureProject menu) these were not listed. When I downloaded them manually they wouldn't install. Saying they couldn't find PictureProject.
PP Transfer kept starting up when I connected my camera. I tried to turn this off in the preferences but there was no option. I had to open Picture Project.
EXIF information for pictures taken with other types of camera is not displayed.
Update: The 1.61 updater also didn't work. It gave an error about not finding a system folder. A new install worked fine with no loss of functionality.
Additional Canon Image Browser notes
Features are grayed out in the edit window for no discernible reason. Seems to be Autofocus view here that I can't access.