[Update 13/4/2013] It has been a few weeks with Linux Mint 14 (Unbuntu) on my Dell Inspiron 15z 5523. From a software side, Mint is running perfectly. Except for a few extra features lacking in Cinnamon desktop (which I am sure they will integrate sooner or later), it has been a quick, solid system all around. Battery life is about 4 hours with wireless enabled, surfing the web and listening to music.
The only complaints I have is with the hardware. First the resolution of the display (not a touch display) is too low. For most things it is fine, but attempting to work on multiple documents is not very convenient. An external monitor could solve this.
The other problem is with the keyboard. Compared to the trackpad, the center of the main typing space (the position of the spacebar, for example) is shifted slightly to the left. The result is that, when typing, my right palm hits the trackpad often, causing the mouse to go flying across the screen, deleting text, etc. Again, not a software problem, but a hardware design problem. For anyone who types a lot with the built-in keyboard and has the trackpad enabled, it can be annoying. Again, easily solved with an external mouse and/or keyboard.
Installing Linux Mint 14 on a Dell Inspiron 15z 5523.
Disabled UEFI to boot.
Wireless works out of the box.
Intel works video out of the box.
Sound works out of the box.
Webcam works out of the box.
LAN connection not working (does not show up in network connections)
sudo apt-get install linux-backports-modules-cw-3.6-quantal-generic
After reboot, it should show up in network connections.
To be able to use the GeForce card, Bumblebee is required. This is recommended anyway because if the driver is not installed then the battery life will be about 2 hours (about 6 hours estimated after install).
NVIDIA GeForce 650M: https://wiki.ubuntu.com/Bumblebee
In my case the bumblebeed service was not starting, so if I wanted to run optirun it would fail. Try this:
If it is asking if the service is started, try 'sudo service bumblebeed restart'.
If bumblebee does not start on reboot, use this (last entry):
I was getting about 108fps with glxspheres, and battery estimation doubled.
Disable bluetooth by default (can turn on again if you want)
Fix huge panel icons in Cinnamon.
Right click on the panel, click panel settings, click "use customized panel size" and "allow cinnamon to scale panel text and icons...".
I've not tried the sd/mmc card slots or HDMI out yet. I will update as I find anything else.