Brushless gimbals in general are much weaker than the servo based options as the motors never product much torque, but are much faster for smoother video. That said there is no gimbal that can handle all cameras due to the balancing issue. I am not sure what the weight of your canon is but unless its similar weight to the gopro you will need to use a larger gimbal with it.
The Sony Nex gimbal that we sell is great but if you want to use your gopro with it you will probably need to add some weight to the gimbal in order to get it balanced properly. So if you want one gimbal for both then that's the way to go. But this gimbal takes abit of time to tune since its not plug in and go like the FY G3.
As for your current gimbal, you might want to spend some more time as the problem could just be due to your settings not being quite right, if you dial down the P gains the vibrations should stop.