I installed with this unit about a month ago along with the external Sirius tuner. I've had a bit of time to really tweak this unit and play around with all the settings.

The sound stage:
Consists of a set of JL VR650CSi (6.5" components) and extra JL 6.5" midbass drivers in a custom kick panel enclosure. I've yanked the stock 6x9's from the back and left the hole as dead space (I've since replaced the speakers, more in the review). The sub is a Rockford Fosgate P3 12" DVC in a custom built vented box (to be replaced with W12v2 when I get the chance). Amps driving the system are JL 300/4 and JL 500/1 slash amps.

The unit:
The navigation on this head unit is superb. The single operation navigation through the control knob is different from previous years Excelon units, so it took some time to really get used to. Previously I had one of the first Kenwood head units to support MP3 audio, it's death was tied to the D-Mask design. This unit overcomes the problems with the D-Mask by just using detachable face security. When testing audio stage on the default settings, I had to turn the sub box a complete 180 for the sound to feel right with the test disc. Later (after reading up on the manual) I found I could bypass this using the digital time alignment and phase adjustment. This is when I put my Clarion ProAudio SR6985 6x9s back in for some testing. I muddled around and dropped the gain on the rear deck still giving a good front stage fill and then changing the time alignment made them sound almost nonexistent (Perfect!). I thought this was the end of the end, but I was wrong. Playing around some more, I turned off the internal amplifier (runs almost cold to the touch after 1 hour of operation) and set the Sound Management System up according to specifications. The front components churned out even better quality sound than previous default setup. The rear fill didn't sound like it was there, but when changing to the back seat, you could still hear them with the front components still the primary source (the way it should be). The final tweaks are not really needed (adjusting the lows middles and highs). The sound quality improvement from the previous Kenwood head unit is absolutely fantastic, it is almost like going from stock to aftermarket the quality gap is so big. There are tons of other features on this head unit that I doubt I'll ever use, (the G-Meter?) but at least they are there if ever needed. Downloadable images, motorized face with angle variations for viewing, dual zone audio, Bass Management System, remote... tons. For the price, this is one of the best head units I've ever purchased. Loaded to the gills with features and amazing quality to boot. I liked this unit so much, I bought a second one for my wife's car just so I wouldn't be without when I'm driving hers. A little further tweaking with the equalizer gives you another set of options to shaping the audio how you like. At first I thought it was just another four band parametric equalizer, but not only can you set the curve, but you can change the attack and decay through the Q. Also, you can change where the boost peaks at. For example, low end can be modified at 60, 80, 100, or 120Hz giving absolutely amazing control over the audio spectrum. This can be changed individually between the front and back speakers, also independent of the subwoofer. Another nice feature is the subwoofer can be switched off with the press of a button (excellent for cruising into your own neighborhood and want to keep a low profile of your audio setup).

The Cons:
There are very few features of this unit that I'm not happy with. For one thing, to use the full features of the ACDrive, you have to purchase an upgrade of the software that comes with the unit (PhatNoise). PhatNoise Media Manager (web site not available, but PhatNoise is) is the same software used on the Kenwood Music Keg and the DMS PhatBox. If you don't purchase the upgrade, you can still create MP3 audio CDs, you just won't have the features of an mCD after the initial thirty days. The mCD offers the ability to jump through to different songs by genre, artist, album etc without the need to directory sort your music. That is an excellent feature when moving from one style of music to the next on a packed disc. However, even if you purchase a Music Keg, you still have to upgrade the software to get the full use out of it, so I guess it's just expected. Another problem I have with the unit is the three line text display. Although excellent, it's not even close to consistent. The regular tuner only gives limited options to text customization and restricts placement on some of the text blocks and graphics. The way I like it set up is to have the clock display in the upper right hand corner with the spectrum analyzer in the upper left. The song information on the third line in "Artist - Title" format and station information in the middle. You can't do that with the normal tuner but Sirius tuner you can. I can understand the regular tuner does not have a full complement of text options that the Sirius tuner has, but not giving the option to put the spectrum analyzer and clock on the first line is an over site in my opinion. Another problem I have, there is no information on how to create my own graphics and animations for the head unit. I'm restricted to using what was already made on a pre built web site and some of those are quite horrid in retrospect. I'm going to see if I can reverse engineer the format and post a how-to online. On some of the previous Kenwood units, like the KDC-X969, they offered an animation authoring system and a way to convert images for "Wallpapers". On the other hand, Kenwood is one of the slowest companies to update their web site.

Conclusion:
The audio quality is nothing shy of superb. The number of useful features is excellent. Navigation is tricky at first, but after a few weeks of working with it, you can navigate almost anything without looking. The learning curve is a bit higher than I would like, but with everything you get in this unit it's expected. The price is a little higher than I would normally pay for a car stereo, however this head unit is not for the fair audio motorist. I would highly recommend this unit to audio tweakers or those who just like to "set and forget" who want excellent sound quality. The look of the unit is very clean and not as cluttered as the previous years KDC-X879. The only other thing I can think of that would be slick is to offer an LED blue along with the green and amber back light options. Outside of the cosmetic indifferences I have with this unit, I would purchase the same thing if I had to start over.

I'll post pictures and videos if anyone is interested.