Our test unit came in a compact white and sky blue retail box. Inside, we got the standard accessories. The charger looks bulky, but it's only a 2A, 10W unit (no Quick Charge here). Then there's a microUSB cable and a one-piece headset. The headset is not particularly impressive. If you're going to use that Wolfson codec to its full potential, we'd recommend using your own headphones.
There are also a few freebies inside the box - a clear snap-on case and a screen protector. Make sure you double-check what your local store lists as "inside the box" as the contents may vary from region to region.
The Vibe K4 Note measures 153.6 x 76.5 x 9.2mm and weighs 158g. That's the same size as the Vibe X3, except lighter. A Xiaomi Redmi Note 3 is about the same size too, slightly shorter and thinner, though.
The Lenovo Vibe K4 Note departs from the K3 design, in a good way. The phone is built on a metal frame that is exposed around the sides of the phone.
The back is made of a soft-touch polycarbonate, which is a nice tradeoff between a premium feel and practicality. Metal dents so easily, glass is always at a risk of shattering, while polycarbonate can take a beating. The gentle texture of the material is also great at hiding fingerprints.
This back cover is removable, by the way. A warning sticker stops you from attempting to remove the battery under it (if you value your warranty), but here you can at least access the three card slots. They are technically separate slots, but due to their positioning you can't really swap SIM2 without removing the microSD card.
The K4 also manages to pull off what has eluded HTC in recent years - the bezels actually feel small, despite having both stereo speakers and capacitive keys on the front. Everything feels tightly packed, we can't point to a part of the front that's not occupied by something.
At 5.5" we think Lenovo could have considered placing the Android keys on screen. Especially since the Home key doesn't have to act as a fingerprint reader.
A bigger concern is that the capacitive keys are not backlit - in the dark you have to poke around blindly. You get used to it after a while, but still it's an odd feature to omit.
Above the screen is the 5MP selfie camera, placed in an almost-but-not-quite central position, the proximity and ambient light sensors and the notification light are in the upper right corner.
The fingerprint reader is placed on the back, below the camera, which helps keep the front tidy. Some find this position more natural than loading the Home button with additional duties and we mostly agree. Our single complaint is that Lenovo put it too close to the camera and you may regularly smudge the lens as you unlock the phone.
The fingerprint reader doubles as a gesture area. It can snap pictures (great for selfies), but it can also get into the normal interaction with the UI - serving as a Back button or an App switcher.
The reader is always active (even when the phone is locked) and it needs under a second to detect your finger, check it and unlock the phone. Your index finger naturally rests on the reader when you hold the phone and it's equally comfortable with either hand.
Next to the metal area that houses the camera and fingerprint reader is a dual-LED, dual-tone flash and there's not much else going on at the back.
The back itself has a gentle curve, going from 9.15mm at the thickest point (the centerline) to 3.8mm at the sides. The metal sides have a slight roundness to them too, making the phone quite comfortable to hold (the back cover's perimeter is a bit sharper than we would have liked, though).
The hardware buttons are on the right side of the phone. Both the Volume rocker and the Power key are narrow but protrude enough to make them comfortable to use.
At 76.5mm the Lenovo Vibe K4 Note is not the narrowest phone, not even by 5.5" standards, though the iPhone 6s Plus is even wider. If you've ever used a phablet for a day, the size of the K4 won't surprise you.
The phone's weight strikes a good balance and along with the curved back, it makes it very comfortable to hold. The matte back offers a lot of grip, something else you don't get with metal or glass backs.