This RX1 very much reminds me the very 1st Walkman Sony introduced back in 1979. It was the very first time we had a very portable personal stereo, and now a very portable FF camera. I would love to own the Canon 1DX, but even if I can afford it, I just can't see myself carrying it with me on vacations.
I see this RX1 for two types of end users:
1. A backup camera for professionals shooting FF DSLR2. Enthusiasts wanting FF in a very portable form factor, especially for low light shots
I agree it would be ideal if camera supported built-in EVF and interchangable lens. However, I would not want to sacrifice size for interchangable lens.
I can see myself using the RX1 as my primary camera, and my Pansonic GX1 m43 for UWA and longer zoom shots.
Well done Sony!