Let me start off by saying this is the best head unit I have owned, but my experience is kind of limited.
Ok, first off this thing is very easy on the eyes, has a sleek and clean look to it with lots of neat display settings, etc.. Currently I don't have any other upgrades to my sound system (items are in-route to me) but the SQ was much greater than that of my old Sony Xplode head unit and the functionality is superb. There is a 7-band equalizer which is displayed in HZ so you can really have a good idea of where you are tuning your sound at. The lowest is 50hz and the highest being 12.5Khz. At the touch of a button you can control the sub level, loudness and cut-off frequencies.
The USB function if one the main reasons I went with this unit. It is a rear usb and rear aux and they give you a 4ft extension for the usb so you can run it to the glove box, dash, etc....great for using the flash drive.
The Source level adjustment is a neat idea but after playing around with it I determined that the cd and mp3's sounded too muffled when trying to match it to the FM setting. The constant is the FM so you cannot adjust the level of any FM frequency which *****.
What else....let's see, there are 3 5v pre-amp outlets, one for sub, one for fronts and one for rears.
A lot of reviews I had seen had people complaining about the controls but I honestly thought they were a piece of cake and literally took about 15 minutes to figure things out. Yes, the remote is a nice feature to have as well, but I'll never use it unless I'm outside the car listening to tunes from a distance.
This is most definitely a HU that needs to be amp'd. The max rating is 50Wx4 and an RMS rating of only 14Wx4. I had to keep the volume at like 45 just to drum out the humming of my exhaust.
All in all I would rate this head unit a 9/10 especially for those of us that are beginners to moderate audiophiles. I am really looking forward to seeing the output once I get things amped and better speakers put in.