i have a grom unit and the second gen units are quite good, they support mp3 via any usb storage device, including a phone in mass storage mode. aux in via 3.5mm stereo jack and ipod. it can be selected between modes, sounds better then cd and works well.
very occasional freezes but then again i run 320k mp3's, all it requires is to be reset (power off and on).
all in all for the price it's a fantastic solution, i have a 120gb hdd with hours worth of music and i find myself never using the radio or cd anymore :)
Hey, just a quick question to save me having to pull the headunit out.... i run a big clarion vtec amp off the factory head unit, which would require an intermediate box to supply the amp cables. Does anyone know if that boxes plugs into that external cd changer port, or if it just uses the original speaker wires???? (might be a stab in the dark but im reaalllllly interested in this product!)