I am saving up to buy either one of the quads from quadkopters.com
1. QK 400 FPV KIT
2. Hunter mini h quad carbonfiber frame.

I know how to fly multirotors but this will be my first multirotor build. I really like the size and look of the hunter but QK400 seems to be more powerful and hence could carry bigger battery. I also want to know if the Hunter quad can be fitted with the KK 2.1 board.

Thanks for your help.

Yes you can fit KK2 on the mini h quad. Please check this topic. I am using KK2 on hunter.
http://www.rcindia.org/multirotors/new!-qk-hunter-260-arf-kit-build-log-review