If you've been researching gimbals, you may learn that not every gimbal works well with every camera. Because these gimbals have to be programmed according to the size and weight of your camera you should choose a stabilizer that works best.
If you're looking for a Ready-To-Run 3 Axis Gimbal for your new Panasonic GH4, you may want to give the Silk Gimbal from XPROHELI a look. Designed specifically for smaller cameras similar in size of the GH3/GH4/BMPCC/Sony A7s, the new Silk Gimbal seems to offer everything you could want with the ability to expand to more options. Take a look at the video below.
The Silk Gimbal from XProHeli can be mounted to multicopters, stream FPV, and even upgraded to control pan/tilt wirelessly from a remote operator either handheld or in flight.
YouTube member BeTerrific managed to get an interview with the company at NAB2014. The video also shows some very stable footage from the Silk Gimbal.
Keep in mind the Silk Gimbal is specifically targeted to cameras sized around the Pocket Cinema/GH3/GH4/Sony A7s. If all you need is a 2 Axis Gimbal (no pan stabilization) for smaller cameras, and you need something Ready-To-Run check out the CAME 6000.
For anyone shooting with a Canon 5D camera or larger your best option for a full 3 Axis Gimbal (and less than half the price of this Silk) is the CAME 7000 (see my video here) [DIY].
Now if you're not the DIY type and looking for a full 3 Axis Ready-to-Run gimbal for cameras like the Panasonic GH4, this Silk Gimbal looks like a great product. Made in the USA from a small company with extensive experience in building gimbals is an added benefit for those who think they'll need the customer support. Priced for less than $2K (found here).
XProHeli Silk Gimbal 3 Axis Brushless Motor Stabilizer GH4