I have an A&K A&Futura (SE100) and have no problem copying playlist created in JRiver Media Center to my player, this is using a Windows 10 laptop. I do not have experience doing this using a Mac, though I imagine the software is much the same across all platforms.
The only trouble I have is with syncing music. An initial sync will go perfectly, but if I add new music to my library, and go to sync it to my player, the sync list will say that some of the music that it wants to sync is not on the player, when I know for sure it was previously synced. It wants to sync it again creating extra copies of the same music while also adding the new music I added to my library. Media Center does not give you the option to make your own sync list, it makes one for you with the options you have selected, either, "All Audio," "All Images," or "All Video," or some combination thereof, and then you can choose individual or a combination of playlists that you have created. That is it.
So JRiver Media Center leaves a lot to be desired in that respect. Hopefully they can correct this and add some new features that would allow you to sync just recently added music or the ability to create your own custom sync list for adding music to HD music players.
Sony's Media Go software worked perfectly for me, but they stopped supporting and updating the software. Since then I have not been able to find a single media center software that has the complete list of features and options that work perfectly for me for managing my music library and being able to sync music using the options I need with my A&K HD music player, and believe me, I have tried all of the major players. But, JRiver Media Center has come the closest, but I also have to use Windows Media Player (which I hate using) to be able to create a custom sync list to add music. You would think with how expensive A&K players are, that they would have their own media software that works perfectly with their players. But, nonetheless, I am addicted to my A&K. It looks amazing, has easily some of the best sounding players on the market and they continue to innovate. I have owned an HD Zune, and a Sony HD Music player prior to my A&K, and checked out, researched, and tested numerous other contenders, the A&K beat all of them in my estimation.
Hope that helps give you some food for thought with your decision on whether or not to move to an A&K music player.