Funny that we should be excited about such a basic feature, but Atomos has does a really nice job with the playback functionality in the Shogun HDMI/SDI 4k recorder. Download it here if you haven't updated yours already.
What surprised and delighted me about it is that all of the scopes, exposure, and focus tools work during playback of recorded footage. Don't think we had that on the old Ninja 2. Super nice feature to make sure you haven't clipped any highlights or crushed any shadows or missed focus before calling your shoot a wrap.