I really like the APM 2.7 flight controller. If you buy the master set it comes with leah-6h gps and 915mhz or 433mhz 2 way telemetry. Also I was amazed at how easy it is to install and operate using a laptop to control the telemetry. You just go to the Arduino copter wiki site and download mission planner and theres alot of information on installation and setup/wiring. You can get em cheap and fast on ebay and amazon.