Let's me attach all my stuff and then it stays out of my way. Varavon has been producing some surprisingly quality gear in the last little while. Their Armor GH4K Pro camera cage was not the first cage dedicated to the GH4 (and GH3) to market, but in my tests, strikes a very good balance between price, quality, and features.
The unibody aluminum cage is very thoughtfully laid out with cutouts for all the critical controls and doors, includes an HDMI and mic cable retaining systems, and stays out of the way so you can focus on shooting.
Yes, I like it and am happy to make it my new cage for my Panasonic GH4.