Yep I think I'm returning it. Don't get me wrong it's a terrific phone but it's not without its issues. I'm averaging about 3 and a half hours screen on time, I disabled all location because that seems to shoot up Google services to the top of battery consumption, to be fair I think that may be a lollipop issue tho as the nexus 6 also exhibits that. The biggest reason tho is because despite the beastly processor it doesn't seem as fast or fluid as my lowly nexus 5 on 5.1, the screen is much better and I vastly prefer capacitive buttons on amoled screens, nexus 5 looks incredibly washed out in direct comparison. Camera is good but I don't take many pics, nexus 5 in HDR mode is plenty good to me.
Compared to the Nexus 6 I think the s6 is definitely more fluid, more manageable in one hand and has a sharper display but boy stock lollipop and huge display and 6 hours of screen time are hard to give up, I think the note 5 will be the one to get once you get used to the bigger screens. Having that gorgeous of a display on a 5.1 panel kinda seems like a waste.
Overall I feel like it's overpriced. Same battery life as my nexus 5, and nowhere near as enjoyable for media consumption as nexus 6. Considering their respective prices, I can't help but feel that the moto x 2014 and HTC one m8 are a better buy, those two devices are just as fast and even more fluid than the s6 in my experience and both screens are perfectly adequate despite not being in the s6 league. Moto x routinely got me 4 hours of screen time and the one m8 got me 5.5 ish. Feel in the hand is just as good, moto x in particular feels ultra sexy and is an ergonomic champ given the bezel or lack thereof.