There's something about the D840 that screams Mercedes Benz. The curved metallic details on the front look as though they've been ripped off a brand-new E-Class. Fortunately, unlike a Mercedes, the D840 is very pocket-friendly, measuring only 12mm thin.
You can buy the D840 for free on a monthly contract from Carphone Warehouse, Orange or Vodafone.
You wouldn't be mistaken for thinking the Samsung D840 bears an uncanny resemblance to the LG Shine. It's thin, it's silver and it has a reflective screen, but this Korean-made handset is no doppelganger. Its screen isn't as reflective as the Shine's, there's no scroll bar and it's slightly thinner.
On closer inspection, you'll notice that the D840 is actually much more similar to its older relative the Samsung D800, which had a similar casing but lacked the silver paint job -- and was slightly thicker, too.
Due to its thinness, the D840 felt comfortable in our trouser pockets and it didn't feel too heavy either. It's wide enough that you don't need to grip it with a pair of tweezers to make a call though, and it won't feel as though you're holding a chopstick to the side of your face either.
For such a thin phone, it's great to see that accessing the expandable microSD slot is really easy, as it's not inconveniently positioned behind the battery but instead placed on the right side of the phone.
The slide mechanism is really smooth and there's a handy ridge just underneath the screen to push the top section open. Further down the top section there's a four-way navigation button with an okay button in the middle, marked 'i'. Annoyingly, the i button will take you to the Web browser from the start page and not the menu.
Hidden behind the top section is a completely flat keypad. Relative to other flat keypads, like the one on the LG Shine, we found it okay to use. It's more difficult, however, to distinguish clearly between each key compared to a keypad with more defined and protruding keys.
Our only other design niggle with the D840, other than the small cancel key and flat keypad, is the camera on the back, which juts out and ruins the smooth lines of the rest of the phone.
Eight months ago, the Samsung D840 would have been a cutting-edge phone in terms of features. Indeed, it has an almost identical feature set to the Samsung E900, which came out in July last year. Unfortunately, compared to the latest handsets it's a little lacklustre.
The 2-megapixel camera is dated compared to the D900's 3-megapixel one, and it doesn't have auto-focus, which means photos come out blurry if you move while taking one. The LED photo light isn't particularly good, only working at close range.
The music player supports MP3, ACC, ACC+ and e-AAC+ formats. You can listen to music via the loudspeaker, or you can use the proprietary headphones. Unfortunately, it doesn't come with a 3.5mm jack adaptor and you can only use the proprietary headphones, which don't come with any MP3 controls built in. There's also no FM radio, a feature lacking on many Samsung phones.