I have to agree with jamezr here on the Note 5. Myself I am typically a big Nexus / AOSP fan, and don't really care for Samsung and HATE Touchwiz.
But I picked up the Note 5 back in August, I am running the Darthstalker ROM with Arty97 Kernel and HOLY CRAP
this phone actually blew my mind, I had no idea a Samsung phone could be this good, honestly, did not expect this whatsoever. This thing is super crazy fast, and hot butter smooth, ZERO lag, and battery life I routinely get like 6h Screen On time, not uncommon to reach 6.5h or even 7h Screen On time.
My previous phone was the Motorola Nexus 6, also tweaked running a custom ROM, I had that Nexus 6 dialed in perfectly, to it's fullest potential, and it was a smooth fast phone, and I can honestly say the Note 5 is actually smoother and more fluid feeling, and way batter battery life. The best I could ever squeeze out of my Nexus 6 was like 5h to 5.5h Screen On time, on it's best days.
Honest question, if AOSP and Nexus is supposed to be so good, meaning no crappy Touchwiz, and is free of bloat, and supposedly lighter system, why isn't battery life that great compared to the Note 5 ? The Note 5 has a 3,000mAh battery, the Nexus 6P a 3,450mAh battery, and the Nexus 6 had a 3,200mAh battery, yet the Note 5 wins the battery over both those phones. And the Note 5 doesn't even have the "Doze" feature yet.
I found the same thing way back on my Note II, I also had a tweaked custom TW ROM on that beast, and that phone gave me ridiculous battery life, like 7h Screen On time, and at the time, no AOSP ROM could even touch that, or Nexus phone.
In my case, I am running a custom ROM and custom kernel on the Note 5, which makes a MASSIVE difference compared to stock. This ROM is debloated, no BS apps, and I can delete all the other crap I don't want with Root Explorer which i did, and that helps save battery. Plus the overall system tweaks the ROM does to the phone, is night and day compared to stock.
My final point, I am actually satisfied with my phone for once. Normally I am itching to upgrade and swap to a newer phone after a couple months, but this custom tweaked Note 5 just feels so good, I see no reason to get rid of it right now. What else would be better ? Yeah the Nexus 6P is a sweet phone, but that's a side grade to me, not a major upgrade over the Note 5. What other high end 5.5" to 5.7" sized screen phone bests the Note 5 today ? I guess I'll wait till the SD820 phones start coming out, and specifically the larger 5.5" + sized phones.