I auditioned both the JC3 Jr. and the MX-VYNL. I preferred the MX-VYNL by a little bit, but I can easily see someone preferring the Parasound based on their system and listening preferences. In my system the MX-VYNL sounded a little more relaxed and nuanced. However, the Parasound was very precise and others might prefer it for that reason.
The MX-VYNL comes with a very cheap wall wart power supply. I upgraded it to a more robust unit (Swagman Labs), and that made the unit even more organic sounding.
I should mention that I've never really been fan of Parasound gear. I find it to be very well designed and good value for the money. The sound usually strikes me as technically flawless but lacking any emotion. So, take my thoughts on the unit with a grain of salt.
Just my two cents,Scott