Here's a short clip, somewhat adulterated by YouTube, of a test of this inexpensive gimbal and controller that I bought from goodluckbuy.com. The Goodluckbuy SKU is 98952, you can look at it by entering that in their search engine. It's made to mount on a Phantom but it's not hard to work up a mount for most any copter.
Here I'm flying it on my DJI 550 Hex "The Witch." I didn't use the provided vibration mounts but rather some stiffer "lord" type mounts I had lying around. Also there are rubber grommets involved.
This gimbal comes without a shred of documentation and I haven't yet figured out how to find the appropriate software. However, it works "out of the box". The only problem is a slight off-level lean on the roll axis, which I've fixed for the moment by simply shimming one end of the GoPro. Build quality is very high. It's all aluminum so not super light.
In this video I've intentionally left bits of the airframe visible to show how hard and well the gimbal is working.
The entire 8 minute flight is as smooth as the 29 seconds seen here.
Slightly off-topic: This clip starts with the hex under manual control in "stabilize" mode, approaching a Geofence that starts at the weed line. When the hex hits the fence it goes into RTL and heads home. It overshoots home (the red landing pad) and neatly turns back to it and ends up right where it should be, at which point I take back control and the clip ends. The slow flight home is my setting, and I think the overshoot might be a result of settings I've made as well, as I'm looking for smoothness, not speed, when I'm tuning.
I'm excited by this gimbal. The YouTube video doesn't really do it justice. If anyone else is using one of these I'd like to hear from you.