Atomos recently released their newest 4K recorder, the Atomos Ninja Inferno specifically aimed at the GH5 crowd. The recorder boasts some very nice features including ProRes recording in 4KUHD 60P 4:2:2 and a maximum frame rate of up to 120fps.
The Ninja Inferno packs a lot in a small package for the reasonable price of $995. Compare that to a 7" SmallHD monitor at up to $1499 which has no recording features and the Ninja Inferno makes for a great buy.
Understandably they had to cut back on a lot of accessories to get what is essentially an HDMI only Shogun Inferno down to $995. My one gripe is that they failed to include a HD Dock like all their other recorders. I was able to find a USB 3 to SATA cable on amazon for $11.95 which works just as good and about $40 cheaper than the Atomos version.
So if you're looking for an external recorder to match up with your 4K camera the Ninja Inferno makes a good argument for "must have" accessory. The monitor also features HDR, LUT preview, focus and exposure tools to satisfy even the professional filmmaker.
You can check the Atomos Ninja Inferno at Adorama or