My friend, Andrew Bloedel has come to the Bay Area several times recently. When he saw my 'fliers' he got the "bug" to build one himself. I told him that I had lots of parts, and could give him most of the stuff needed.
I looked at all the pieces I had lying around and realized that it would take some time to build one using my "leftovers", so instead, I bought a partial kit - an S500
This $139 kit has everything needed except the radio, controller and battery. It doesn't include a gimbal or camera.
It comes with an APM Controller, GPS+compass, 30A ESCs, 2212 920KV motors and 10" GemFan props. The frame is fiberglass with carbon fiber rods for the landing gear.
We put it together. I designed and printed a new battery holder so that it could carry a big battery - 8000mAH/3 Cell. We did the assembly and installed the radio.
It flew fairly well, but on one flight, we did have a glitch with the compass, but I fixed that by adding a 220 ohm pull up resistor to the SCL line. The craft was low on power, and while it flew, it definitely had problems when the battery voltage got low. Below 11V, the motors had barely enough power to keep it in the air.
So we modified the arms slightly by drilling out some holes and changed the motors to SunnySky X2614 / 1100 KV models.
What a difference! It really flies well now, and climbs like a rocket.