Mike C: There was a post about a less expensive grip when the RX100 was announced. It provides another option for those too frugal (for whatever reason) to consider the Franiiec grip. They appear to be very good and come in four types. If I purchase an RX100, I'll purchase the Franeic grip.
This topic puts a whole new spin on the term "Get a grip on it". :-)
I have one of the other grips (Flipbac) on mine right now. The problem for me is that although it is providing a better grip, it is very close to the lens (it has to be mounted on the flat front) and my finger is forced to the botom portion of the grip only. I'll certainly give this new one a try.