Thanks for your replies. I am not going to try whatever on my iPad. To be honest, I just get into the idea that some of the apps on Cydia are really trustworthy. I was on business trip recently and by chance I was talking all way long with some experienced jailbreak'er on the plane. Few days after I explored Big Boss apps and somehow it get me convinced to go for it
I was asking about restoring just in case I will need to upgrade to 4.3 or newer for any reason or claiming warranty.
Stock 4.2 OS is quite good for me. The only problem it has, from my perspective, is the multitasking "crap". The device cannot handle multitasking with so limited resources yet it clutter all the apps in background. Just saw on youtube how it is handled in 4.3 and I am very disappointed - it is still long way from being usefull. Besides I really doubt the wisedom to upgrade into an OS designed to run on a dev with twice as much RAM and twice the processing power inspite whatever the manufacturer claims. Just like we were being triced to install Vista some time ago
Anyway no point to elaborate the reasons. Thanks again for clarification on the backups. I feel somehow more safe with modding my iPad