Just to avoid misunderstandings, iTunesAgent (now called Notpod) DOES NOT SYNCS PLAYLISTS on iTunes.
It just syncs the music CONTAINED in certain playlists on iTunes.
This means that if you have multiple playlists in sync with files of different nature insight, it will blend all the files, and you will loose file control.
That's the reason why it is completely useless for most users (except the one that are use to play a single playlists).
Moreover, it does not support a full customized destination pattern creation, you will have at least 1 subdirectory level created.
On portable music players (iPod etc.) all the files are ALWAYS stored into the same directory, leaving to the player the ability to organize music according to mp3 or m4a tags.
This because each sub-directory level increase EXPONENTIALLY the time needed to scan/organize the music (the time needed to access files).
Most of the work is already done.
The just need, after files have been copied, to create a text file with same name of destination playlist name configured, ".m3u" extesion, place it into main declared destination folder, and write pattern/FileName inside.
I really can't understand why they are not willing to implement this 5-minutes change.
Talking about players, I've tried many of them, included the ones referred into this post.
I've find out that the best ones in terms of no-lagging, sound quality, sound adjustement, media-art recovery, Reply Gain support and FULL lock-screen support (without to pass from several lock screes, the player one, the system one, etc.) is PowerAmp.
That's actually the most used android player, that should be a reason behind that
There is a time-limited trial version on Google Play, give it a try.