Does the base station have an ethernet port, or is it WiFi only? hard wired (etehrnet/rj45) is a requirement
Do you take the doorbell off to charge? yes, not had to do it yet so I have no idea how long it takes
My only worry with the smart doorbells, is that they're very easy to take off, and it wouldn't be much faff to stop someone nicking it. - it's got a special key to remove it, but yep it could be nicked if you really wanted to.
Google Hello have a scheme in the US that they'll replace stolen doorbells, but that doesn't exist in the UK. I've actually managed to thread some thin steel cable around mine and back through the hole that the wire feeds through. It's enough to make it a ballache to remove, although not impossible, it should prevent any opportunist thieves from trying.
There's plenty of videos on youtube showing how you can remove the Google Hello doorbell in 5-10 seconds.