How does 800 series compare to older Z-Wave versions?
You can find a comparison of Z-Wave 800 series and 700 series at that link.
Which version of Z-Wave should I use?
If a device isn't Z-Wave Plus do not buy it. That leaves you with 3, Z-Wave Plus versions to consider: 500 series, 700 series, and 800 series. Do not buy any 500 series / Gen5 devices — they're end of life and makers no longer issue proper bug and security updates. Only consider 700 series and 800 series Z-Wave products and only purchase 800 series wherever possible.
What is the wireless range of Z-Wave 800 series?
800 series Z-Wave can wirelessly communicate over a distance as great as 1.5 miles / 2.4 kilometres. That's when it's operating in Long Range mode. When it operates in mesh mode, it can communicate over a distance as 0.25 miles / 401 metres. Compared to 700 series Z-Wave, that's an upgrade of 150% in Long Range mode and 175% in mesh mode.
Are Z-Wave 800 series hubs / gateways available?
Z-Wave hubs and gateways using 800 series aren't availabe - yet. But Atrim is presently engineering just that solution.