So I am trying to figure out how to sync my photos between 2 computers. My desktop and a Laptop and also a nas. I want to be able to edit photos from both my desktop and my laptop. But I don't want to have to constantly import and export to keep my files up to date. also I don't want to have to have the files themselves on the laptop or desktop. Just the nas it self. Also I am using widows 8 pc's if that's a factor, but I do plan on buying a mac. I also don't yet know which nas system will work best with this so I have not yet bought a nas.
One way is to put the catalog file on an external HD, and move the external HD back and forth between your desktop and laptop.
Other people use something like Dropbox for the catalog file, so it can be accessed by both computers, but the drawback to this is you must wait until Dropbox has updated the file on one computer after you have used it on the other computer (and there might be other drawbacks too, I have not tried this myself, but you might want to read the threads here about this topic)