i currently have the JVC KD-SH9750, and love it. it's been my experience that JVC units are rather user friendly, don't skip from bass, and play scratched CD's better than pioneer. i had a pioneer in my car before this JVC, and hated it. the user interface sucked bad:mad: it was very picky about playing CD's, especially burnt ones. one of my friends has the premier 650, and the biggest complaints he has is the user interface and the round button on the right does not have much "feedback". basically you'll think you pushed the button for skipping to the next track, or whatever, but it doesn't. other than that, it's a great unit. i can't say anything about panasonic, cause i haven't used one yet, and none of my friends have one. alright, enough with personal experience, let's get technical:
JVC pros:
7 band built in EQ. lets you tailor the sound.
98 dB S/N ratio
1728 color variations
JVC cons:
2 pairs of preouts
2 volt outputs (i believe)
aux input is optional accessory
no satellite radio controls
Pioneer pros:
XM ready
3 band EQ (better than none at all)
built in crossover
3 RCA outputs
Pioneer cons:
2 volt outputs
limited color option
aux input is optional accessory
poor user interface (IMHO)
Panasonic pros:
5 volt preouts
3 sets of outputs
Sirius sat radio
aux input built in
Panasonic cons:
one color display (blue)
no EQ
if you are planning on using amps for all your speakers, the panasonic would probably be the best choice. you'll get the front, rear, and non fading sub outputs all in 5 volts for better signal transfer. however not having a built in x-over or EQ makes it not my first choice. if you don't plan on amping all the speakers, i'd get the JVC. using the 7 band EQ to tailor the sound to your liking is a great thing to have. the pioneer would be my second choice, because it does have the 3 outputs, and it at least it has the 3 band EQ. but the best advice i can give you is go to stores and actually use the HU's before you buy one. just cause one has good specs, or someone else like it, doesn't mean you like it. you might hate it. it's all about personal preference, and with those 3 HU's, you can't really go wrong with any one of them, so it all boils down to which you like the best
