If you weren't interested in the Z1, then you'll definitely want a quick recap of the camera performance. Sony's claim is simple: The Z1 family sports one of the highest-resolution sensors on the market. The company's also thrown in a bunch of technology borrowed from its standalone cameras, including that BIONZ image processing. It even claims that the sensor here is the "equivalent" size to that used in the firm's Cyber-shot line, but that doesn't tell us much with so many other factors involved. The idea clearly was to have media, photos and video be a central feature. The reality is that it's not the best camera we've found in a phone (that would be the Nokia Lumia 1020's PureView cam), but it's certainly one of the more capable Android cameras we've come across. If we're determined to find it a "best" title, then it's the best camera we've seen on a Android phone.

So why is that? It comes down to a number of factors, not least of which is the pixel count. There's also, of course, the fast f/2.0 27mm-equivalent G lens. That wide aperture allows plenty of light to pour in, giving it consistently solid results, even when conditions are somewhat dim. It also provides a good depth of field, ideal for those who like a bit of "bokeh" -- that blend of sharpness on the subject, and out-of-focus background.
As for noise, the usual telltale sign of a cameraphone? When viewing images at 100 percent (quite a task at 20.7 megapixels) you'll find some artifacts, along with color washout in areas around the edge of your subject, or where the lighting contrasts with the metered area (e.g., if you have the metering mode set to central, the edges might suffer). All that said, this was a small detail we noticed while checking some of our sample shots for this review. What's more, smoother edges render quite well. Clouds are an abundant resource in London at this time of year, and we were actually impressed by how the textures and moody grays came out, really showing off the rich palette at the Compact's disposal.
Photographers will most likely be happy with the camera's "Superior Auto" mode, which generally delivers pleasing results: rich colors, good white balance and even exposure. If you're more of a tinkerer, you'll want to flip into manual mode where you can take control of the ISO, exposure compensation, white balance and metering mode, et cetera, and have much finer control over the results. If video is more your thing, we'd encourage you to keep the SteadyShot feature on for everything except static objects, as camera shake will otherwise render your videos a little, well, shaky to say the least.
Software

Historically, Sony's been relatively kind to Android users, with minimal skinning and unobtrusive add-ons. That's pretty much the case this time around, too, although the company has left a few sticky fingerprints around the interface to remind you of its presence. Mostly this means that where a Sony app or service is available, in addition to a standard Android one, you won't have to look hard to find it. That means it's "Album" instead of "Gallery," "Walkman" instead of "Google Play Music," et cetera. If you've ever used an Xperia phone, you'll most likely already be familiar with this, but it's all easy to remove, ignore or replace, should you prefer.
Unfortunately, the native onscreen keyboard here drove us crazy. Have you ever had a dream where your life depended on typing something, or dialing a number on a phone, yet for some inexplicable reason it became the hardest thing to do? That's a bit like using the swipe mode on the default keyboard. I'm experienced in both Android's stock swipe input, and third-party options like SwiftKey, and have never experienced one like this. Writing a short message frequently made me feel like I was drunk, with the words onscreen often barely resembling my intended prose. Perhaps it's a case of getting used to the slightly smaller keyboard -- maybe I was too vigorous in my swipes -- but there was definitely a lot of cussing, deleting and hunting-and-pecking.

To counter this minor annoyance, we were reminded of a neat addition to the multitask screen we've seen in previous Xperia Z models -- an understated bonus. Press the familiar double-square button, and you'll get the currently running apps all stacked on top of each other as usual. At the bottom, however, are some additional options. On the left is an arrow that, when pressed, reveals shortcuts to configurable favorites. To the right of that are buttons for some additional quick apps. We'd actually call them utilities, really, as they include a calculator, basic browser, notepad, timer, audio recorder and screen grabber.
The other interesting thing here is that these apps operate slightly differently than those from the main menu. If you open up the browser, for example, it launches in a new window that floats on top of whatever you are/were doing. Effectively, it brings multitasking if you want to quickly Google something, perhaps while lingering over an email. In that case, you can shift your attention briefly without ever having to close the email window. This isn't earth-shattering, of course, but it's a nice inclusion -- and one that's easy to overlook, precisely because it's mostly hidden away.
Performance and battery life
What about the phone's overall performance? This is where we take our hats off to the fine folks at Qualcomm. Whatever tea they were drinking when they came up with the 2.2GHz MSM8974 chip inside this phone, we'll take two packs. Given the shared DNA between this handset and the Z1, we expected the numbers to be similar, but to our surprise, the Compact actually bests its predecessor in some benchmarks.
This is reflected in our usage of the phone, too. We never felt like we were taxing that hefty quad-core engine. We threw video at it, along with graphically intense games like Grand Theft Auto, and the Compact took it all in stride. We did have the camera app crap out on us twice, but that was during the first five minutes, and it never happened again after a restart. Equally solid is the performance when it comes to calls and internet connectivity. All our calls sounded clear, while London's O2 network regularly delivered speeds around 30 Mbps -- definitely in the high end for my neck of the woods.
While we're handing out gold stars for performance, the Compact deserves a nod for battery life. It's one of the specifications that took a hit in the downsize, but the 2,300mAh cell actually does a sterling job. In our usual battery test (WiFi on, screen at 50 percent brightness, video looping), it managed well over 11 hours. In more conventional usage, the Compact can last well into day two before forcing you to hunt for an outlet. The even better news is that this is all in standard mode. Sony's added not one, but two power-saving modes that will let you eke out even more juice (at the cost of notifications, backlight and the other usual power-sucking suspects). We'd say you won't really need to bother with that; instead, save those options for when you're planning on staying away from civilization for a little longer than usual.
The competition

If we're talking mini flagships, we can't ignore HTC's One mini or Samsung's Galaxy S4 Mini, especially given that they both run Android. HTC's offering ran a similar price to the Compact at launch, though you can now pick it up for about £100 cheaper. That's a good thing, too, as its 1.4GHz dual-core processor and 4MP shooter (UltraPixel sensor or otherwise), will seem positively arcane compared to the Compact. Samsung's mini S4, on the other hand, falls short on the display (it's the same size, but 960 x 540), the camera (8MP), RAM (1.5GB) and processor (1.7GHz dual-core). The only saving grace is that it's cheaper than both HTC and Sony at around £250 SIM-free. While not a "mini," Motorola's Moto G might appeal to some of the same customers, if a mid-sized 720p Android phone is what they want. The £189 price helps, too. There's also, of course, the iPhone 5c, which, while not a mini, per se, falls into a similar size range.
Wrap-up

There's no point in beating about the bush: Sony's "mini" flagship is what companies should have been doing all along. If you want a top-spec Android phone, but don't want a finger-stretching screen, this isn't just your best option; it's your only option right now. To call it a good all-rounder might sound like we're playing it down, but with the camera, software, display and processor all putting in equally solid performances, there isn't one aspect that stands out above the others. Yes, there is the odd software kink or minor design feature (fluff-attracting glass!), but even then, we're mostly playing a game of fault-finding.
Of course, you could argue that Sony missed the opportunity to improve on an already good phone (the Z1), given that some months have passed since the Z1 was first released. Instead, Sony was content to take that flagship and simply scale it down. That, it has achieved with aplomb. Even if the Z1 Compact isn't the smaller phone you've been waiting for, you should still be glad it exists: at the very least, it might inspire the competition to up their "mini" game. And that can never be a bad thing.
Edgar Alvarez contributed to this review.