Thanks for the replies so far.
No direct bad experiences with generic batteries so far with the RX100, so I'll probably get the ExPro as it's less than half the price of the Sony OEM.
I'm starting to 'get' the manual focus. The main problem seems to be user expectation, the reality is that's operating at the actual f stop, so a lot of the time makes little difference due to hyperfocal distance effects. Wide open things are easier to see.
The proportional control doesn't make discover of the functionality easy either, the fast you turn it the greater the rate of change. The focus peaking helps a little, but is damn crude compared to what I'm used to.
It's annoying that these sort of things aren't properly documented. Not even having a decent manual you can download is just crazy.
Still interested to hear of people's experiences with different card speeds and cases. It also looks like some sort of filter holder for a ND would be useful too.