The HTC One (M8) and Sony Xperia Z2 are very close in terms of design philosophy, yet feel completely different - good for them we must add. Size-wise the two are neck and neck - and these are by far not the most compact of flagships, we'll chalk this one down to the front-mounted stereo speakers and not quite razor-thin bezels.
Overall, the Sony Xperia Z2 is slightly wider - and feels like it considering the angular shape - being slimmer doesn't help much. The HTC One (M8) is 146.4mm tall while the Sony Xperia Z2 is almost identical at 146.8mm. the same goes for weight, at 160g vs 163g respectively.
The Sony Xperia Z2 fits a bigger 5.2" screen and a pair of stereo speakers in virtually the same vertical size as its current opponent. The speakers are etched out of the sheet of (scratch-resistant) glass covering the entire front, and thus a lot subtler than the prominent grilles either side of the One (M8)'s screen.
Opting for on-screen controls, both phones seem to have a patch of unused space below the display -clearly more of it in the HTC One (M8). The Sony Xperia Z2 has a "breathing" LED located under its top speaker. The front cam here is a 2.2MP unit. On the HTC One (M8), a status LED is underneath the speaker grille, with a 5MP front camera nearby for higher quality selfies.
The Sony Xperia Z2 is sharp at the corners and boxy, in contrast with the ergonomically curved back of the HTC One (M8). Sony's flat, glass covered front and back are mounted directly on the steel frame that holds everything in place. The HTC One (M8) has its edges sloping toward the rear, shaping a gentle curve that fits nicely in the hand - even better with the cold touch of aluminum.
That's the material of choice of the HTC One (M8) - there're almost no plastic bits to be seen, Gorilla Glass 3 coating the screen. The brushed aluminum body is one of the hottest in business. The Sony Xperia Z2 is also built around an aluminum frame but none of it is actually exposed. All you see on the outside is scratch resistant and shatter proof sheets of glass. On the sides, the aluminum frame is treated to a soft-touch finish.
On-screen buttons are in-charge of navigation on the HTC One (M8). There's a BoomSound speaker each side of the screen, each under its micro-grilled mesh.
The Xperia Z2's 5.2" IPS LCD Triluminos display with X-Reality engine is impressively sharp, never mind it has "just" 424ppi as opposed to the 441ppi of the HTC One's Super LCD3 unit.
The pair of speakers on the Sony Xperia Z2 aren't individually amplified and the water-proofing is known to have taken a toll on the loudness.
The Sony Xperia Z2 also integrates the back, home and recent apps button into the display.
The sides of the HTC One (M8) feature a volume rocker and two ejectable trays for the nano SIM and microSD card. You'd need to use the provided tool to open them.
The Sony Xperia Z2's sides are more densely populated: a two-step shutter button, a single piece volume rocker and the prominent power/lock button are all on the right side of the device. Above the trio of controls sits the microSD card slot under a protective flap. The left side has a longer flap covering the microUSB port and microSIM compartment.
The top of the HTC One (M8) features an edge-to-edge IR blaster, which has forced the 3.5mm headphone jack down to the bottom. Not an ideal location but the One (M8) gains points back for the IR port letting you remotely control TV sets and other home appliances.
The Sony Xperia Z2 has the 3.5mm audio jack at the top, in what's a clearly more minimal approach to the bottom and top.
The back of the HTC One (M8) features the differently sized lenses of the Dual Camera setup along with a Dual LED two-tone flash. The latter has a natural yellow and an amber LED while the camera is comprised of a 4 MP primary lens and a secondary unit allowing measures distance and depth effects.
The Sony Xperia Z2 only has one of each, lens and flash, but 5 time the resolution. On the other hand, the HTC One (M8) has the Ultra pixel size in its favor. More on that, in the camera chapter later on.
We can safely disregard any differences between the HTC One (M8) and Sony Xperia Z2 relating to size and weight.
What will make the experience of holding the smartphone different is the shape and materials used. The HTC One (M8) is curved and kinda sticks to the hand. The angular Sony Xperia Z2 is perhaps a tad more aggressive but less comfortable to hold.
It's just a little sharp on the hand but not in a terribly bad way. In fact, the HTC One is more slippery perhaps.
We'd say to each its own - both smartphones are built to a really high standard but feel sufficiently different. You won't make a mistake picking either one up. And we suggest you do just that - hit your local retail store and handle both to see how you like them.
In more objective terms than pure aesthetics, the HTC One (M8) has the better pair of stereo speakers and an IR blaster. A proper shutter key and water-proofing are Sony's key advantages.