Getting music onto my Galaxy Nexus has been relatively easy. The part that is frustrating is once it's there... MM doesn't seem to realize it.
When I go forth and play music on my phone and add some tracks to MM, I plug it back in and wait for the scan to complete. The phone shows up in the tree and I can click on the sync button. But when I do, it tells me it's preparing the list of files... but that list never seems to be compared to the files on the phone. Every time I sync, it attempts to copy every selected song to the device. Songs I have deleted from MM never appear in the dialog to delete them from the device. Songs I have added to the phone via Amazon MP3 downloader never get copied back to MM.
This is frustrating as syncing takes hours to copy 1,000+ songs to the phone every single time.