Flash based "fake CD changer" adapters

Does anyone have any experience with any of these, or with any other similar devices in a Gen 2 Prius? The VAIS, GROM and Dension units definitely have the most impressive looking websites but I can't really find too many detailed end user reviews on any of them.

Looking to add the ability to play MP3's off of USB sticks without losing the JBL amp, the steering wheel controls or the audio from the stock MFD and nav...

Yatour YT-M06 - Yatour Digital Music Changer YT-M06 - USB Bluetooth SD AUX MP3 Interface CD changer emulator

Yatour YT-M07 - updated version that claims to support displaying id3 tags - Digital Media Changer M07 - China Digital Media Changer M07 Manufacturer from Guangzhou Yatour Electronics Technology Co.,Ltd.

Wiiki Tech WT-USB - Toyota USB MP3 Adapter (USB1-TYT01)_Car USB Mp3 Adapter

GROM USB3 - Toyota Scion Lexus USB Android iPod iPhone Bluetooth AUX adapter

VAIS MultiMediaLinq - Video,Audio Information Solutions for Toyota and Lexus (iPod integration,XM and Sirius SAT radio integration,MP3 integration,Auxiliary input)

M.Costa Electronic DMC - Car Digital Music Changer-Toyota Small Plug----Mcosta Electronic Technology Co.,LTD specialize in Car MP3, Car digital music changer, iPod auxiliary input.

Dension Gateway 300 - iPhone Car Adapter | iPod Adapter – Dension Gateway 300

XCarlink Model V - Toyota USB/SD MP3 Interface Model V :: TOYOTA :: XCarLink

Zemex v3 - http://www.zemex.de/zemex-v3-bluetooth-adapter-ipod-ipad-mp3-iphone-autoradio/Toyota/zemex-v3-toyota-14-22-1115.html