Thank you guys, i had receive  lot of opinion and really much appreciated.!! after i had reviewed all the opinion, i wish to add in 1 more situation in deciding whether go for ipad mini with retina display or ipad air.
Which is i already owned one ipad 3 aka The New Ipad.
Considering this in to my decision, should i get ipad mini with retina display instead of ipad air?

I have iPad 2, iPad 4 and my most recent iPad Mini Retina and I must say the size of the iPad Mini is perfect.

Although the new iPad Air is significantly lighter for the bigger screen, but having experience with the larger screens, I think they're slightly bulky. I love the screen size of the mini and accessibility/portability is not an issue. Maybe that's just me, but if you are a casual user/gamer, iPad Mini would be perfect for you.