Even before the price drop, I had been interested in the XZ-2 and MX-1 for reasons discussed below.
I'm interested in the Casio as well and I'll tell you why.
As I mentioned, I had been interested in the XZ-2 and MX-1. Both of them have a larger-than-average sensor that is also backside-illuminated. Backside-illuminated sensors are able to collect more light. For example the Sony RX100 and RX100 II have similar-sized sensors except that the RX100 II sensor is backside illuminated, and is claimed to have 40% improvement in low-light sensitivity. As for the XZ-2 and MX-1, I used the DPR comparison tool and the raw files seem almost 1 stop better than those of the Lumix LX7 and XZ-1 which have similar-sized sensors.
Moreover, the XZ-2 and MX-1 have a pretty fast f/1.8-2.5 zoom lens. With the slightly larger sensor and fast aperture, they compare favorably against other compact cameras, providing essentially the same effective aperture as the Fuji X20 with its larger 2/3" inch sensor.
Speaking of the lens, DPReview found the lenses to be sharp, and the Pentax MX-1 has earned a silver award from DPR in its full review. (The XZ-2 hasn't been fully reviewed yet but was noted for having very similar image quality in a studio comparison.)
Besides probably sharing the same sensor and the lens, the three cameras also have a tilting LCD, which I think is very useful for street photography (similar to a waist-level finder) and for capturing more candid expressions in family photos.
Although they share many things in common, there are important differences between the three cameras.
The Pentax MX-1 is in my opinion the most stylish of the three. It also has a genuine brass upper and bottom plate that will wear more gracefully.
The MX-1 has a green button like some Pentax DSLRs. The green button has some useful functions. If you use Program shift, pressing the green button resets to the normal Program mode. When spot metering in manual mode, pressing the green button will give you a normal exposure for the spot-metered target.
One disadvantage of the MX-1 is that it only has one command dial. The XZ-2 and EX-10 also have a single command dial but they also have a control ring / function ring that works like a second command dial.
Here is DPReview's review of the MX-1.
The Olympus is unique in having a touchscreen with a Tap to Focus and Shoot function (like the E-M5). See this video. I think the value of having such a function is in being able to choose the focus point much more quickly.
The XZ-2 also has a hotshoe. Although some people think a hotshoe is overkill for a small camera, I personally think a hotshoe is quite useful for a pocket camera like the XZ-2 because of the unlimited sync speed. (I have an LX5 and found the hotshoe useful. See here).
Among the three cameras, the XZ-2 is also the only one to allow a viewfinder accessory (but it's not cheap). It could be handy when shooting in very bright conditions.
As mentioned above, the XZ-2 has only command dial (rear) but it has a control ring that can be used to change the aperture or other functions.
Finally we come to the Casio, a new player in the enthusiast camera segment.
My very first digital camera (around 2004) was a Casio, and I still have the Casio EX-V7 which I got in 2007, and it still works today. What I like about Casio is that they usually have innovative features. For example, the EX-V7 (and many other Casio cameras) have a function called "Past Movie". When you use this, it starts the video recording 5 seconds before you press the shutter (it's actually continuously recording and overwriting a buffer). Some Casios have a similar function for continuous shooting where you can choose a shot before you press the shutter, called Prerecord Continuous Shutter.
What I didn't like about Casio is that the high ISO performance was just average, and the lenses had small apertures. Therefore it was mediocre for low light. However, the EX-10 now addresses the sensor and lens issues.
Fortunately at least some of Casio's innovative features (including the Prerecord Continuous Shutter) will be included in the EX-10. Other interesting modes include a simulated wide angle (where you can 'paint' a larger field of view), all-in-focus macro (automatic focus stacking), and simulated background blur for portraits (regarding this latter feature, here is a sample - not perfect, but good enough for casual shots; another sample here).
In addition to having some interesting modes, the EX-10 is one of Casio's "HS" (high-speed) cameras. The HS cameras are supposed to have very fast startup time. It also has up to 1000fps video for super slow motion.
The EX-10 may have a shutter speed as slow as 250 seconds (compared to 60 seconds for the XZ-2 and 30 seconds for the MX-1) in manual exposure mode. See here. It also has a bracketing mode that can change two variables over 9 frames (such as white balance and exposure).
In terms of control, the EX-10 features a rear command dial and a function ring (like the XZ-2). For street photography, there is a button on the front that can facilitate taking waist-level photos with the tilting LCD (or can be assigned to other functions). Speaking of which, the XZ-2's LCD can flip up to 180 degrees (for selfies). When flipped to 180 degrees, the XZ-2 has a built-in stand that can support the camera vertically, with the shutter triggered by a gesture.
So if you're in the market for a compact camera for those times when an interchangeable-lens camera is just too large, then you may want to consider these three cameras. At the time of this writing, the XZ-2 is available for $388 and the MX-1 is available for $289 (black) or $249 (silver). The EX-10 is available only in Japan and we don't know yet if it will be sold in the US. Please note that these links are for our Amazon Affiliate account, which allows you to support our blog without any cost to you. 100% of proceeds will be donated to charity. For December 2013 we'll donate everything we get to the Red Cross for the victims of Typhoon Haiyan. Thank you for your support!