HTC has been on something of a winning streak since launching the first One M7 smartphone in 2013.
So it's unsurprising that, one year on, HTC has chosen not to deviate much from its strategy when designing the latest One M9, which aims to fix earlier shortcomings rather than introduce any radical innovations.
Design and build
HTC claims to have "merged the best features" of the One M7 and One M8 when designing the One M9.
Beyond a few small changes, like the phone having a square as opposed to round camera lens, the One M9 looks close to identical to the One M8 from a distance.
With a rounded metal back that wraps around to the Gorilla Glass front, and 'Boom Sound' speakers, the only immediately noticeable design change is that the One M9's sides are a different colour to its back.
HTC has also rethought the button placement, moving the power button from the top edge, as it was on the One M8, to the right hand side.
Some may bemoan the lack of significant changes to the One M9's design, but we're fairly happy that HTC hasn't mucked it about too much.
The metal case makes the One M9 feel noticeably sturdier than most competing handsets, and gives it a pleasing premium feel.
At 145x70x9.6mm and 157g we also found the One M9 fairly comfortable to hold in your hand, and it feels suitably ergonomic thanks to the curved back.
The One M9 is fairly generously stocked with ports, featuring nano SIM, micro SD and micro USB inputs.
HTC has equipped the One M9 with the same 5in, 1920x1080 pixel, 441ppi Super LCD3 capacitive touchscreen found on its 2014 predecessor.
On paper, the screen isn't anything to write home about by today's standards, and puts the One M9 behind competing Android handsets such as the Galaxy S6 and LG G3 which both have densities of 500ppi or greater.
However, we were pretty impressed when testing the One M9 and found the screen more than fit for purpose.
We've never made a secret of the fact that it's difficult to spot differences in sharpness between smartphone displays that break the 400ppi barrier, and so most users won't notice much, if any, disparity in quality.
This remains true on the One M9, where text and icons look sharp and crisp. Brightness levels are reasonably good and in general the One M9's display performed very well.
The only difference we noticed is that HTC has tweaked the screen's colour and contrast settings to give it a much 'cooler' feel than many competing Android handsets.
Samsung, for example, has a tendency to crank up the settings and oversaturate colours in a bid to give them more 'pop', but HTC has kept the One M9's colour settings fairly low key.
We found that colours look noticeably more realistic than on many competing displays. Some will complain that this makes the screen look dull, but for us it's a positive that generally makes it easier to do things like accurately adjust photo contrast and colour balance levels.
Next: Operating system and performance