iPad mini vs Nexus 7, which one is more value for money?

If you just want to be safe and assured, just use the original charger and cable
I only/always used my ipad 2.1A USB charger to charge ALL my phones and tablets irrespective of their original charger output. I have yet to faced any issues past 6 years doing it faithfully. However sceptics will tell you is not safe. So it is really your choice to use non Nexus chargers. And the cables I used is a mix of old Blackberry, HTC and Samsung cables
So when I sell off my stuffs, 99% of the time the original charger/cable is intact

Please be specific . Don't talk in vague terms - what is " drain like water " ??

That is CRAZY. All my android phones and tablets I have used so far , I never have more than 5% battery drain overnight over 7-8 hours and that is with 3G on 24/7 and active mail notice, FB, tweeter notifications is background
My best I have ever recorded is the Xperia Z, Z Ultra - normally below 2 % only due to phone excellent stamina mode. Infact on the Xperia I have used , most of the time is 0 to 1% drain only over 7 hours overnight. My present Note 3 and Nexus 7 ( non LTE)  averages 2-3 % battery drop only overnight over 7 to 8 hours
Battery drain overnight is due to your wakelocks - you need to identify what is waking up your phone and not going into deep sleep. My deep sleep is always at minimum 90 % and above
Go google what is wakelocks or read Note 2 official thread page 1 where there are excellent guides on such
Next time use app BetterBatteryStats to identify these wakelocks

Press power+vol down to print screen, the official ways to print screen on android

I on my 3g over night and it juz take around 12% of my batery , izit too much ?

I recall benny's nexus is not running on stock kernel.
You can always turn on aeroplane mode when not in used.

Try battery saver apps like "juice defender"?

Any suggestions on preferred telcos for data plan? Should I stick with digi as I already have a smartplan. I'm at sarawak

First thing , check your wakelocks first than move forward from there

I repeat there is no fast easy solution to this
And in addition, You need to spend time to study all your apps and see which are often connected to internet to refresh data - you either change the time of refresh or deselect any refreshing if you don't need it

It took me at least few days studying this to be able to achieve this and I use same principles in all my Androids
That is why I can consistently achieved such low battery drain overnight in all my Android phones/tablets. The exception are the Xperia Z n Z Ultra which with its default and proven Stamina mode helps further to reduce the battery drain to often below 2% over 7 hours
I am not the only guy who can achieved such - there are several many others too : check up the Xperia Z, Xperia Z Ultra, Xperia Z1 and Note 3 threads - battery drain of less than 5% over 7-8 hours is common with 3G on

I have even tested those so called battery saving apps to reduce phone from accessing internet and I'd not even want to recommend any as their benefits is minimal. Some users will praised them for its effectiveness but for me nothing beats good old manual method of control

Yes just put the ROM zip in your phone storage and reboot to recovery to install.