In case of landing gears, or legs that are attached to the bottom of the quadcopter, the choice is either done by aesthetic or need. For example, if your drone is solely for recreational purposes, you could choose your landing gear based on what is cool or nice looking. But say you’re filming with your drone, with the camera on the bottom. Without a long enough landing gear, your camera might crash on the ground every time you land, but if your landing gear is too long, it might get in your shot. Point being, I can’t recommend your perfect landing gear, because everybody’s needs vary.
Though, some popular landing gears are:
http://www.aliexpress.com/item/F04766-Tarot-Carbon-Fiber-aluminum-alloy-Landing-Skid-Gear-TL2749-01-for-DJI-F450-F550-MultiCopter/998072692.html(this one is very similar to the one I use)
http://www.helipal.com/dji-landing-gear-for-f450-f550.html (Beware! This landing gear is ONLY good if you’re buying the DJI F450 OR THE F550! It DOESN’T fit on the F330!)
