Simply a comparison between the two. From having used M7 for a year and M8 for around 10 days. This is just the start of it, this is just “at a glance” comparison. Just a start. A photo comparison from both will come later.
Will do this in segments. Lets start with the most obvious change first.
Looks & Design
You can see that they’re both from the same family but M8 is just more refined with the aluminium coming up to the screen now and not having that plastic sides as on M7. For me M8 just looks better, esp the gunmetal grey variant of it. M8 wins.
Sorry M7, you had your chance (and a long life). M8 is simply faster, not so surprising having a faster CPU etc. M8 wins.
Since Beats bought back their shares from HTC in late 2013, all newer HTC phones doesn’t have “beats audio”. M8 instead got Boomsound compared to M7 that got Beats Audio with Boomsound speakers. Just to confuse you a bit. I think that they both sounds pretty good, M8 a bit louder. For me M8 wins.
Here M8 simply wins, since it does around 40% better on battery than what M7 can do. A full day (16-18 hours) is easy to get out of it, it’s a walk in the park where M7 struggled a bit.
Here it’s closer since they both share Sense 6, even though M8 got more camera modes (dual camera setup) and it have the BRILLIANT Motion Launch (tap twice on screen to wake it up etc). Even though Sense 5.5 in some ways was more direct (like in camera), but since both got Sense 6 now: M8 wins, since it got more camera modes and the dual camera.
Worth to upgrade to M8 from M7?
If you have the money: In a HEARTBEAT. Nothing to even think twice about. M7 is still a VERY nice phone. M8 is just better. M8 wins.
But, M8 doesn’t have OIS (optical image stabilization). Makes it bad!
No, not really. I’ve compared recording video with the two and I can’t really tell much difference between those. In regular camera mode: I feel that M8 is quicker to both focus and take the photo, so there you don’t notice it at ALL. But, why no OIS? you can’t do with the dual camera setup. But, you actually don’t notice that it doesn’t have OIS. So. M8 wins anyway.
M7 wins, since it’s cheaper than M8.
HTC One M8 wins this since it beats HTC One M7 on pretty much anything. M8 can be a little slippery since the aluminum comes up to the display, if you have slightly wet fingers: Be careful!