The highest clean ISO sensitivity the XZ-1 produces is really ISO 100; ISO 200 is still quite usable, but you can start to see some noise suppression artifacts. By ISO 400, details begin to smear. Processing raw can help somewhat, but I was unable to produce an artifact-free version of an ISO 400 shot.
In its default settings, Olympus applies a little too much sharpening to its JPEGs. While it doesn't look too bad here, in more natural shots it adds a bit of crunchiness. Also, note the fringing on the highlights.
(1/50 sec, f21.8, ESP metering, AWB, ISO 100, 28mm equivalent)
The camera's generally cool white balance shifts the hue in this red a bit (a common problem with digital cameras). While there's some loss of detail in the brightest areas, the camera does a reasonable job.
(1/125 sec, f2.2, spot metering, AWB, ISO 100, 65mm equivalent)