i have to say this even its just a developer preview, it buttery smooth and features are working well....not a problem for day to day usage....Good Job, Google

What the exact different between ICS and JB?

THE BAD: Navigation is still Gingerbread looking. Background gradients are still pixelated. Most importantly, NO PINCH TO ZOOM IN GMAIL! WTF Google?
The multitasking drawer loads faster when you press the button, but it makes you wait on the dimmed screen while it load the app screenshots. It gives the illusion of being faster.
Different animation based on how you switch to an app (ICS had only one)
Hotword Detection: launch voice search when you say "Google" (when you are running google now)
Jelly bean easter egg
New Developer options:
SD card privacy protection (won't come into effect before the next major release)
Animator duration scale (the window and transition animation options are still there)
Disable HW overlay (not sure what this one is)
etc
In contacts, there is a "Auto-sync app data" option that I think wasn't there before.
Messaging app widget!
New Contacts icon
New share action and intent picker pop out (big icons instead of a list)
Default font seems to be a little thinner than ICS Roboto in some places
NOTIFICATIONS CAN BE DISABLED. This one is a godsend. You can long press on notifications to get the info of the sender app (useful for detecting spam apps)
When keyboard is active, the back button turns into a downward arrow (just like tablet ICS).
WPS PIN setup for Wifi
Wifi-direct has more options (like CM9)
"Add-on dictionaries" : it's empty now until 3rd party keyboards leverage the new API. (I think you would be able to get dictionaries from play store in the future)
Kernel is based off 3.0.31 (ICS was 3.0.8)
Google play music has been updated (Nexus Q settings link, better interface, etc)
Keyboard shortcuts (example: brb expands to "be right back"). Catching up to Apple much Google?
NO ROOT RESTRICTION ON GOOGLE PLAY MOVIES!. I wonder how they pulled this off without compromising DRM.
SAFE BOOT: long press on "Power off" (in the menu that shows up when you long press power button) to get into this mode. Only system apps will be loaded (should come in handy when dealing with rogue apps)
Screen seems to be better calibrated. The colours are more neutral and less yellow.

source : XDA

U cannot tell me here? I cannot really read at that website..

U cannot tell me here? I cannot really read at that website..

dam smooth....

new notification centre....

TY btw

and now buy my OTG cable...

OTG cable?

cable that allow u to connect usb pendrive to ur nexus

Only to nexus? To other phone?

Other phones that can use I have tested sgs2 n galaxy note. HTC Incredible s, sensation, one x cannot

Is there a setting to activate otg or just simply plug and play? Interested to get one

Is there a setting to activate otg or just simply plug and play? Interested to get one

Is there a setting to activate otg or just simply plug and play? Interested to get one

you will need to install stickmount, it will requires root access.

once you have stickmount installed, plug in the usb device (eg. pendrive), then it will create a folder called usbStorage, you can access it by using file manager.

u need install stickmount and rooted ur device