Tested the A7SII and the Atomos Power Station (Guys at JRC were very helpful, find them at http://www.facebook.com/jrentalcentre). The power station solves the problem of batteries constantly running out, but I still found the menu system takes some getting used to (from a Canon user's perspective). That being said, the 4K internal recording + 5-axis stabilisation and needless to say, superbbbbb low light capabilities make this camera my go-to choice for night shoots. Will continue to rent as I don't expect to need it more than 3 times a year!