The FS5 isn't exactly new, its been knocking around for a couple of years. On paper, its not really all that special. A 4k camera that manages 8 bit internal on long GOP that is taxing on processors. It wasn't until it came bundled with the RAW upgrade that it made real sense to finally invest in the form factor, and an investment it certainly was!
So how does it work. Well, firstly you need a recorder that is capable of taking SDI and can record CDNG format or Prores. Currently, the Atomos Inferrno is the best suited, coming in at around £2k once you include the batteries, handle and all the other stuff you'll probably need.
You get a 4-6 second burst of DCI4k at 120fps or constant 2k at 240fps, which is quite a major offer from such a small camera, and of course this all comes in at either Prores or CDNG, so good bitrates and final aquisition.
It does however mean you're stuck shooting on s-log, and as someone who's versed in v-log, this is a whole new hurdle to overcome! But onwards and upwards as they say.