Overall, the S6 Active has been one of the best smartphones I've owned (Apple iPhone 3g, 4, 5, MotoX 2013, OnePlus One. Best screen ever, best camera ever. I've never dropped one of my previous phones (all have had cases). But within a week of owning this one, I dropped it while taking a photo... no damage except for a small scrape on this bad boy. I love that I don't have to have a case on this guy. Water resistance is awesome, My friend had an S5 that he washed under the sink after a 'dirty' meal and water resistance became a 'must have' for me. Battery life has been sufficient for me as it gets me through the day of pretty heavy use with near 5hr SOT and about 30% battery life remaining. Quick charging is awesome for when I just need a quick 'top off'. I find myself using my phone a lot more now that I don't worry about battery life. It is a pleasure just staring at that screen.
Now, the negatives. I replaced TouchWiz launch from day one and changed the theme to the free material one from the Samsung Theme store, however, CyanogenMod for the OnePlus just gave me sooo much more configurable options. The details from the tweaks are amazing. I miss double-tap to wake and some of the off screen gestures. There's just something about the Samsung OS that just keeps me from loving it. The physical buttons do take some getting used to.
Now the possible game breaker for me. I noticed that when multi-tasking, unless I am switching between two very recent apps, that the OS recycles my apps much too quickly. They are on the multitasking window, but when I want to launch it, it has to start from the beginning. This is most noticeable on games since they take quite some time to load from scratch. So multitasking on the S6 (I think in all variants) is pretty poor. The worst thing is, with the Active variant, we'll probably be considered the last to get pushed updates since we are limited in population (and only on AT&T). This memory leak is documented across the internet and there may be hope in 5.1.1, but I don't have much faith that the Active will get that for quite some time. Anyone else notice this? I don't have a memory cleaner app, I've downloaded and tried to disable 'bloatware' with package disabler, but really, switching between open apps is much slower on this phone than on my previous phones.
I love the phone, dislike the software, but wouldn't trade it in for any other flagship or upcoming flagship.