Having seen the dji frame versus the hobbyking frame - and also seen / had a go with a Naza versus the KK2 - here's what I'd do.
Buy a DJI frame from a DJI dealer and then buy a KK2 board and everything else from hobbyking
I was - still sort of am - considering the Naza Lite - but the KK2 is too good to pass up.
My impression is that the Naza is for people who want to get something into the air safely - and almost anyone can fly it with gps on. Also if it goes wrong it 'should' return home.
I've read that aerobatics & flips etc are not really Naza territory.
On the other hand if you want to learn to fly yourself - and you can enable auto level which is ace - the KK2 is for you. You can set it up in the field from tame to silly flip monster in seconds.
Also different firmwares are great. I've just bought my 3rd