The Good: The YotaPhone 2's rear e-ink display lets you read e-books for long periods without draining much battery -- a feature no other phone has. It has decent all-round specs and a good front screen too. The Bad: Its high price puts it among the top-end phones, which it fails to justify. The e-ink screen suffers from ghosting issues, the software for customising it isn't particularly easy to use, the camera doesn't impress and there's no expandable storage. The Bottom Line: Although the YotaPhone 2's e-ink display is wonderfully novel, and can result in much better battery life, the phone needs to be considerably cheaper if it's going to be a sensible purchase over other Android phones. Making your phone stand out in an increasingly crowded world of similar products isn't easy. You can cram a laser into the camera, try curving the display round the edge like the phone's melting, or, in the case of YotaPhone, slap a second display on the back. was certainly novel, and its e-ink second display showed promise. Its poor quality and lack of compatible software meant it never really shone though. Not willing to throw in the towel, the Russian handset manufacturer is back with the second-generation YotaPhone -- the YotaPhone 2, would you believe? -- and it's seen a whole bunch of changes.It's had a complete design overhaul, with better quality displays front and back, a more powerful processor and it makes better use of the e-ink screen. It's available to preorder in the UK and the rest of Europe from today direct from the company's website. Launches in the US and Australia are on the cards, but no official date has been confirmed.It costs \u00a3550, SIM-free and unlocked, which converts directly to around $860 or AU$1,025. That puts it squarely in the price range of the smartphone elite -- blockbuster phones like the iPhone 6, , Sony Xperia Z3 and LG G3. Doing battle against these guys is difficult enough for established names, let alone for an unknown Russian brand. Its rear screen certainly makes it unique in the smartphone world -- no mean feat -- but is it enough to justify its high price?Two screensThe entire point of the YotaPhone 2's existence is the second display on the back. It uses e-ink technology, which isn't backlit like typical LCDs and only uses power when it refreshes what's on screen. It's therefore incredibly power efficient. You'll find e-ink screens on Amazon's Kindles, whose batteries can last up to a month on a single charge.On the YotaPhone, the idea is to use the LCD for tasks like Web browsing, texting, gaming or watching videos, and the e-ink side for reading e-books or other long pieces of text. Not using the LCD for long periods will save power and, as e-ink screens don't use backlights, it should be easier on your eyes too. At least, that's the theory.The YotaPhone 2's e-ink display is improved over its predecessor both in the quality of the display and what it can do. It has a 960x540-pixel resolution, up from the measly 640x360 pixels of the predecessor, which helps make text look sharper and more easily readable. It still has problems though. Its biggest problem is with "ghosting". When the display refreshes what's on it, a faint trace of the previous screen is left behind. Although YotaPhone said this is a bug in the software and will be fixed, it was also a problem on the first model, so my hopes aren't high for a big improvement here. I'll update this review if an update arrives that fixes the issue.The rear screen has three main modes: YotaCover, which acts as a lock screen, displaying images from your gallery; an Android-like set of four homescreens with widgets for weather, favourite contacts and app icons; and a mode where it simply shows the same Android interface you see on the LCD side. Programming the rear screen is done almost entirely using the Yota Manager app, which can be very tricky to use. It requires a lot of tapping around, sometimes at random, trying to find little settings icons to select just which app icons or contacts you want to display. I also found that even after setting up my Twitter account, it still wouldn't display any recent tweets on the Twitter widget, which I'd have liked to remain visible. The e-ink screen is fully touch-enabled (unlike its predecessor) so you can swipe around Android as you normally would. It's far less responsive than the LCD screen and much less sharp, so it's no good for quick texting or emailing, but it does bring more functionality to the rear display than its predecessor had. The biggest draw is that you can use apps like Kindle, Kobo or Google Books, giving access to a far wider selection of literature than was available using only Yota's e-book service.Pressing and holding the home button on the LCD side allows you to instantly take a screenshot of whatever's on screen and display it on the back panel. It'll then sit there until you replace it -- even if the phone's battery dies completely. If you're on your way to an unfamiliar pub with 2 percent battery and you need to save the directions, you can take a shot of Google Maps and keep it on the back for reference. Handy.Simply being able to use Android immediately makes the YotaPhone 2's e-ink screen considerably more useful than its predecessor's, but it still has plenty of room for improvement -- specifically with the ghosting problems, making the widgets easier to customise, and improving the look of Android mode, which is still far from crystal clear. Perhaps the biggest hurdle though is in simply learning to use it and figuring out which of your existing day to day activities can be done on the rear display -- thereby using less battery power. In this sense, there's a steep learning curve and it's likely that you won't see an immediate advantage in using the back screen unless you're particularly keen on reading e-books on a small phone, instead of a dedicated e-book reader.Main displayIt's not all about the e-ink screen though -- there is still a regular LCD display on the front. It's a 5-inch affair with a full HD (1,920x1,080-pixel) resolution. That gives a pixel density of 440ppi, which is enough to make the display extremely crisp. Icons and text are clearly displayed and high definition images have great clarity.It's bright too and has strong colours. The black levels are nice and deep, which results in great contrast. It's an impressive screen overall, as good at displaying the basics of Twitter and Facebook as it is showing off glossy Netflix shows and your photography collection.DesignThe YotaPhone 2 has had a significant design overhaul from its predecessor. It both looks and feels considerably more refined. The square, boxy design is gone, replaced with a more attractive oval shape. Instead of sloping off halfway down the phone, the back panel is gently curved, making it very comfortable to hold.It's still rather plain, but I feel that works in the YotaPhone's favour -- it hasn't tried to clutter either side with pointless additions like chrome edging or fancy metal-effect grilles. Instead, it looks very functional. The front glass panel is unbroken except for the speaker. It's completely flat too and runs right to the edge of the body, which I rather like. At 145mm long and 69mm wide, it's not so big as to be cumbersome to use and at 145 grams (5.1 ounces), it isn't too heavy either.