I just removed the jailbreak and can share that it was not so easy, it was holding my breath for a while...
Playning with cydia apps (most rated ones all over the forum) I found places when my iPad gets frozen. Besides 99% of the apps are iPhone oriented and looks ugly on iPad so I just decided to get rid of it.
I found on some posts that simple restoring via iTunes will not remove cydia apps from the iPad and they will eat space indefinitely
so before restoring I uninstalled everything from cydia including cydia itself - that was bad! From that point I was left with little silver apple on the screen
Hopefully there is DFU restore mode (google how to turn it on...) and I got new clean iOS on my iPad.
Now there is another
big dissapointment although I now have 4.3 there is no multitasking gestures
I just found on the web that it is not any problem of my iPad, apple really decided to not release it to consumers. Now I am waiting for proper jailbreak for 4.3 or update of official multitasking gestures. At least backgrounder and activator from cydia worked perfectly.