We've only been using the RX100 for a few days, but our initial impressions are mostly positive. We haven't been able to look at its Raw output yet, but JPEG image quality is certainly a step above what we'd expect from Sony's high-end small-sensor Cyber-shot compacts. The RX100 is very responsive, both in terms of autofocus speed and general picture-taking, and this combination of a genuinely compact form factor and enthusiast-level performance and customization is very attractive in everyday use.
Despite being a Cyber-shot, the RX100 takes many of its menus from the Alpha series. This means they're somewhat dense, multi-tabbed menu system, but there are plenty of options, including the ability to adjust the upper and lower limits used by Auto ISO (A feature previously reserved for the range-topping A77 and NEX-7). With this in mind, we're disappointed by the incongruously laggy zoom operation in playback mode (a frustration that many Sony users will be only too familiar with) and as we get used to effective touchscreen interfaces in other models we find ourselves wishing we could control AF point selection by touch. These, however, are minor niggles in the grand scheme of things.
Of slightly more concern in use is the slim, free-rotating Control Dial around the RX100's lens barrel. This control takes quite some getting used to. Although it works wonderfully for adjusting focus and lens zoom, the lack of detents means that changing functions like ISO or exposure compensation - which are set in discrete steps - feels distinctly odd at first, especially if you turn the artificial 'click' sound effect off. Accidental operation is a danger too, when working with any control which offers little or no haptic feedback. More than once during our shooting, with the control ring set to control exposure compensation, we've ended up with over or under-exposed images as a result of inadvertent ring rotation.
Overall though it's hard not to be impressed by the Tardis-like RX100. A list price of $650 will raise a few eyebrows (since we suspect that a lot of consumers will miss the significance of the large sensor and simply see a small, expensive camera) but this is inevitable. Ultimately, Sony has managed to pack a 1-inch sensor and a 28-100mm equiv. zoom lens into a body that fits comfortably into a shirt pocket without sacrificing usability or manual control, and that's no small feat. We can't wait to start running the RX100 through our full gamut of studio and real-world testing, but until then, feel free to examine and download our gallery of sample images and let us know what you think of the camera in the comments.