[Xperia Z5 Compact General] ACA7:
Thanks TheEndHK and supercakefish for the replies. I'll add a few more bits.

There are three main reasons as to why I'm considering Z5C over my S6: Size (I find the Z5C size ideal for single handed use, S6 is slightly too big, although mostly manageable), battery life (again, the S6 isn't terrible but more on that later) and memory management (yeah, the S6 is pretty bad in this respect). I also wouldn't mind additional performance/snappiness all-around but I'm hearing that Z5C isn't much more responsive than the S6. At least not consistently so. I'd really really appreciate a super responsive Android phone (no Nexus please, lacks waaaay too many features and the camera app is for kids, feature-wise). Although S6 isn't bad, I'd like some occasional lags begone. Doesn't sound like Z5C delivers that though, despite the very significant advantage in the number of pixels it has to render. I don't consider Z5C an upgrade over the S6. I'd just like a smaller flagship with not many compromises compared to the full-size ones. Although I absolutely love the super-sharp QHD AMOLED on the S6, I can sacrifice that for better performance, battery life and manageable size. The 720p on a 4.6" screen isn't bad, although FHD would've been nice/preferable. But for that compromise I'd expect near lag-free experience in every aspect, which doesn't seem to be the case on Z5C, according to most users and reviewers.

Battery life-wise I was keen to see if I could live with the Stamina Mode permanently on as you can exempt certain apps of your choosing so it doesn't shut everything down when the screen is off. This sounds exactly like the type of control I'd like to have because I know which apps I want running in the background while the screen is off and it drives me bonkers when I find out a darn app has kept running in the background and drained my battery when I wasn't looking in the last few hours. Another intriguing feature in the Sony phones is the ability to manage your Wifi signal intelligently. As I can't be bothered turning Wifi on and off each time I go somewhere where I have Wifi access, I keep it on all the time. But with Sony phones you can set it so that it turns Wifi on when there is a known network in range. Just sounds like a good battery saving measure but again, not sure if it works well in practice. As with everything, all is in the execution.

Interestingly, about two weeks ago I got a software update on my S6 that seems to have improved standby time significantly (among other things like Stagefright fix). I was getting frustrated that some apps were just draining my battery in the background and hiding under the Android System guise in the battery stats, so Sammy has done something about this. The downside? I think they've gone even more draconian with the memory and background process management to the point where it "optimises" (i.e. kills and doesn't let them run in the background) if you haven't used the app in the last three days. This is useful in some circumstances but not in all. I have apps where I don't physically touch it but it needs to run when it needs to (like SMS syncing and call recording) apps. Not sure if it's killing all of those. Similarly, LastPass seems to have lost its ability to draw over other apps to fill after the update. This is really bad!

When it comes to the camera, I have to say, I'm really blown away with the S6. Features, speed, quality, everything. Just works as it should. I don't mind the more saturated colours it produces, it's just a pleasure to view to my eyes. I know it's a personal preference thing, so I'm not saying this is objectively better. I'm just saying I'd rather the vivid colours than the flat but more accurate ones. The things that worry me about the Z5C's camera are:

1) Low light performance (at least compared to the S6)

2) Lack of OIS (which contributes to the first point too)

3) Panorama shots. This is a particularly baffling one on the Sony phones. How can you have a 20+MP sensor yet produce 5MP panoramas where the stitching is all visible and you can't even stop it when you want (apparently you have to go all the way to the end of the sweep path)? To me, this is a big let-down. The panorama on the S6 is absolutely spectacular. I've taken numerous shots and examined them bit by bit to find where the stitching is, couldn't see it. Not one. And the end result is phenomenally detailed photos with everything (like exposure, colour, white-balance etc) pretty much the same as a single shot. Again, if panorama photos aren't your thing you might not care about this at all. They are somewhat important for me as I don't mind the occasional one when I get away.

4) Last but not least, lack of automatic exposure adjustment with touch focus (or at least I couldn't find this). As some of you would know, LG and Samsung cameras (or their apps, should we say) readjust the overall exposure of the shot to the area of focus. For instance, if I have a dark and a light area in the photo, if I wanted to focus on the dark area I'd touch there and the exposure would also readjust accordingly. Sure, this would probably overexpose the light areas (without HDR) but if I'm focusing on an area, I probably want that area to look the best. In my view, this is the easiest way to use your phone's camera as a point-and-shoot, which is what it is for most people. At least having the option (for instance have this in Auto mode but not in Manual) would be a really good thing because sometimes you just don't have time to switch to manual and try to get the exposure right.

Sorry guys, I felt the need to unload!