While the biggest impact it has had on my video recording is the provision of a larger (and more manoeuvrable) screen for monitoring than the one on my camera, I primarily bought this as a recorder. This model can record to either SD card or external SSD drive: you can choose which is your primary drive and when that fills up it can switch to the other).
Having said that, it has a wonderful range of monitoring tools (just see the specs) and the video screen is bright and provides incredibly crisp and bright visuals. I haven't delved deep into colour reproduction quality, but it's sufficient for my basic needs.
It has two plates for Sony NPF batteries, but can operate on just one. If two are plugged in, it will drain one first and then the other, which presumably allows swapping out of dead batteries (I haven't had need to do this yet, as my 970s seem to be good for 90-120 minutes, so haven't run out yet).
This has HDMI pass through as well, but encountered some difficulties here. Specifically I thought I could pipe the 4k feed from my camera to this for recording, and pass the signal through to my wireless HDMI transmitter. However, the latter cannot handle more than 1080p - and while the camera and the transmitter seem to negotiate a 1080p signal even when the camera is set to send out 4k, this does not happen with the Video Assist. I'm not too experienced with video products, so this might not be a surprise to anyone else but me. It's not a huge problem though.
The VA comes with 6 1/4" threads - evenly space on top and bottom. The USB-C connection is on the 'bottom' of the VA (thoug note that you can configure the VA to automatically flip the screen if it detects it is upside down) and, as reviewers on other sites have noted, this is uncomfortably close to the 1/4" threads. In particular, it rules out a great many monitor mounts being used on 2 of the 3 threads on the base!
Note that sound monitoring always seems to be on. To workaround this, I've configured it to monitor some of the other 16 channels it supports that are not used by the camera. This doesn't affect recording.
Finally note that a recent software update means that this allows you to use your camera as a webcam via the monitor's USB-C connection! Not a reason to buy this perhaps, but certainly a need additional function.
