Are there advantages/disadvantages of doing a hand held sync to a folder versus just doing a standard conversion to a folder? I usually just do a conversion and tell it to not convert any files that are already there?
It's better for several reasons.
1. If the folder is eventually going to be transferred to another device for playback then it can sometimes be nice to hardcode the R128 leveling using DSP studio. This is what I do for my car head unit.
2. It can automatically export playlists pointing at the new directory.
3. If you are syncing playlists or smartlists, then subsequent syncs will only transfer new tracks.
4. You can set handheld sync to automatically sync to the external drive when it is available, therefore syncing dynamic playlists (see 3) will keep the external location automatically updated upon connecting the drive (for external backups) or program start up (for permanently mounted drives).
I've synced MC to my phone 2 years ago: some 16,000 mp3's including 128 mbit-conversion. It took over 2 days to finish it - in the meantime I couldn't use my phone.
Now I want to sync it again (my phone was stolen, so I have to do it all over again).
Is it possible to export the whole bunch to my computer HDD first, so I can copy the result of that to the phone? That would go quite faster I think and that would make it possible for me to use my phone in the meantime.
My feeling is that your sync speed is being limited by MTP. I would look into enabling developer mode and using adb push to sync large numbers of files to the phone, in my case this results in a 5-10x speedup.