I tried doubletwist and it simply wouldn't work. The number of songs imported to doubletwist didn't match the number of songs in my iTunes library. Also, none of the playlists I created in iTunes after installing doubletwist would import to doubletwist. Maybe there was a settings option that I missed or something.....I don't know. I just know that I couldn't get it to function the way that I wanted, so I stopped using it.
AFT is a bit of a pain in the *** for music because you can't just drag a playlist over, but for pics, videos, and data files, it works just fine for me.
Which Windows OS are you using? I have a Windows 7 laptop that I rarely use, but maybe my S5 will play a little nicer with that instead of my Mac.