This size is not compared because I am trying to show something that most people can't see instead (low light performance, corner sharpness, etc).

For size, it will be very obvious to the buyer. Just like it is very obvious iPhone will be smaller than any of these and 5d mark iii will be bigger than this two. 

Both are good cameras and depends on what you what to pick on, if you want pocket ability, RX100 is the way to go. If you want better shooting experiences (more buttons and dials, better menus, etc)
, LX series is the way to good. So as the 24mm wide end, do you need it? If you need it, RX100 will be out. Also do you plan to use the hotshoe, maybe for a flash or electronic viewfinder? These stuff a bit more obvious, what I try to bring to the table is again, the combination of the sensor with the lens.

p/s your LX3 mode dial...    can also see your hand in the shutter button, haha.