It lets you access all sorts of files on your home PC like media, document, and pictures. The set up was a breeze even though I don't keep my files in the default windows location. If you keep them in the default locations it's ready to go once it's installed on the PC.
If you have a large music (83gb) and picture(17gb) collection and you reboot your phone the music and picture app must resync with your PC. This took almost 3 hours via a 3g connection.
3 hours of downloading data has two effects. The first is it killed my battery. The download knocked it from 70% to 20% and had me thinking it not would last the rest of my day. The second is it used 71mb of data. This is not an issue for me as I have an unlimited plan but on a 2gb plan a few restarts a month will put a dent in your data limit.
My final verdict good idea poorly executed. I will use Google music for my music needs and deleted the music file from MotoCast on the PC. I will rarely use the photo option and if I do will force close the app after I get what I need.
On the plus side when I access my movie folder the only data used is while streaming the selected file.