Wow, I don’t know if you’re purposely misleading or if you just don’t have any knowledge. Let’s start here.
Display This is not “difficult to determine yet”. As the link from DisplayMate that I gave you stated: ”The Galaxy S6 matches the Galaxy Note 4 in overall display excellence and record performance and joins it as the Best Performing Smartphone Display that we have ever tested.” The AMOLED display on the Galaxy S6 is far and beyond anything else out there in terms of brightness, color accuracy, viewing angles, performance in high ambient light, color modes, etc. It’s an en entire generation ahead of any real competition. On the other end of the spectrum you have Sony’s Z-flagships, which have among the worst displays of any flagships out there: they are worse than HTC, Apple, Motorola, Nokia, LG and Google’s flagship phones. So no it’s not “difficult to determine yet”. Sony can make their best display to date with the Z4, and still not be even close to the S6, Note 4 or S5 in terms of display quality. That’s how far away from each other those two are.
Speakers: Z4 is gong to have refined larger front facing stereo speakers. Z4 is going to be a clear winner in this department.
First off, audio is more than speakers, and I was talking about audio output (headphones). Secondly, if what you are mentioning is what’s going to be on the Z4 (source?), then sure: the Z4 will have better speakers.
Battery
This is where I have difficulty taking you seriously. Your first mistake is to include Z3 into the discussion, when the Z4 will be equipped with the much more power-hungry Snapdragon 810-processor. Secondly, your source is not very good for two reasons. The first is that it only gives us a list called “battery life”, and second because the battery life between the Galaxy S6 and the S6 Edge is so varied, when this should not be the case, and is also not the case in all other sites that have reviewed these phones.
Until Anandtech finish their tests, GSMArena is the best source, and gives a much more defined battery assessment that takes the phones through several tests. Let’s see what they say:
The Galaxy S6 and S6 Edge (with 2550 mAh and 2600 mAh battery times) give the same battery time, which is:
Endurance time: 73h
Talk time: 19:48h
Web Browsing: 10:56h
Video Playback: 12:12h
For fun, let’s see how the Sony Xperia Z3 with a much bigger battery (3,100mAh) fared:
Endurance time: 85h
Talk Time: 23:13h
Web Browsng: 12:03h
Video Playback: 11:47h
With the exception of the video playback, the Z3 is better: somewhere around 15% better, which is far from impressive. We are after all talking about a significantly bigger battery (550 mAh). And that is also ignoring the fact that the S6 and S6 Edge have 80% more pixels on their screen (which, interestingly, had little relevance in the most display-oriented test; the video playback, where the Galaxy-phones won). Which brings me to another sentence of yours:
Additionally your argumentation regarding number of pixels equals higher battery consumptions is not correct, as it has been proven that the S6 new display consumes 20% less power than the 1080p display on the S5.
This is called ‘technology’, my friend. The S6 display may consume less power, but that is because of the improvement of the display technology that Samsung uses. Their improvement in display technology is only one of many innovative advances Samsung have done with the S6. Now let’s get back to battery time.
You are right there may seem to be some issues with the 810, however if we follow that logic of yours the difference between the M8 and M9 battery life in the test is 47 minutes. Therefore the estimated battery life for the Z4 will be 8h 42min, which is still way better than the S6.
Let’s first start with sources. Again I will use GSMArena for consistency, but you can be my guest and use Anandtech’s review of it too, which gives a similar result.
The M9 with its 2840 mAh battery get’s
Endurance time: 62h
Web Browsing: 7:31h
Video Playback: 8:21
As GSMArena mentions, their M8 (2600 mAh battery) had 12:30 in Web-browsing (70% more) and 10:10 on video playback (20% more). Talk-time deteriorated after the Lollipop-update from 20h to 14:15h, which is less than the current M9.
Overall, we are talking about 20% worse battery life on the HTC One M9 after the M8 – not taking the bigger battery into account (which means even worse battery life).
Don’t also forget that HTC have underclocked the Snapdragon 810 CPU to be able to perform this “good” with their battery life.
So if we were to assume that the Z4 got the same screen resolution as the Z3. Underclocked the Snapdragon 810 similarly as the M9, and was fitted with the same battery size as the Z3, we would be getting 20% less battery performance than the Z3 (now I’m being very generous). What does that tell us? Well it tells us this:
Endurance time: 68h
Talk Time: 19h
Web Browsing: 9:50h
Video Playback: 9:30h
Now, compare that again to the Galaxy S6-models and you will see that it is not quite as good as the Galaxy S6-models in any of the categories. Whereas they win clearly in video playback, and to a degree on web browsing, they are only a bit ahead in talk time and endurance. What does that tell us? It tells us that the S6-models are superior in every shape and form. Why, you might ask? Well, the S6-models have
Software: Sony wins
Yes, correct (although I can only speak for Touchwiz pre-S6, and based on reviews out the new Touchwiz is actually pretty nice).
Camera: S6 is looking good here, however I believe Sony are likely to create a camera that is going to be on par.
They haven't been able to do this in the past. But this is the least that is demanded of them. With 1080P and worse battery life than its predecessor, it will look really bad for the Z3. Especially considering that the S6 has such things as 1440p-screen, the best display out there, UFS-memory, better-performing chip, fingerprint sensor and whole new design. Having a camera that is on par with the S6 is something that will be demanded of them.
But either way, based on the specs and performances that it is predicted to have, the Z3 will be a "little" catastrophe of a release, just like the M9. They can thank the 810-processor, along with Samsung's amazing S6-release, for that. The S6 will be the superior Android-phone in 2015. Period. I'm not saying this because I'm a fan (in fact I've never liked Samsung and always hated Touchwiz, and have always stuck with Google's Nexus devices), but because it's simple fact. It's stupid for either of us to deny this fact.