I am also having a bit of trouble deciding between the JH16 and JH13.
How would you describe the sounds of both IEMs relative to other headphones?
Headphones I listened to include the Beyerdynamic DT 880, Sennheiser HD380, Ultimate Ears Triple.Fi IEM, and the Audio-Technica ATH-IM04 IEM.
You like bass heavy music? If you don't mind a bit of bass boost, then go with the 16. But, please keep in mind that bass boost usually lowers the clarity in the sound, if you like to monitor sounds.