Since I am new to Android, I don't really buy into the whole "Stock Android" experience. In my few days with the Note 5, I thought it was really good software. Really don't know understand the whole TW hate. For timely updates... Not huge on it I guess? I mean, it would be nice. It's just that on my iPod I was stuck on iOS 6 (3 generations behind) and I pretty much stopped caring after iOS 7. I did get iOS 9 on the iPad Mini but I use devices for the apps and features, not software.
What I do really care about, though, is if software is gonna change the phone in 3 years. I am not saying I want updates; it's fine if I never get another update ever again, if the current version works great. I've heard a lot of good things about TW amidst all the hate, with most people (that actually owned the phone) reporting that there's no lag, there's just that ram management issue (which I didn't even notice when I had the Note 5. It's sad but I actually got used to having every single app reload on the iPod, so I wasn't even using the multi-task capabilities of the Note 5). If I end up getting the Note 5 instead, I really need it to hold out for at least 3 years. Looking at things, it seems it should hold out with its specs. What I don't understand is phones like the Note 4 lagging out after a year.
As you can probably tell, I am leaning towards the Note 5. I wanted the Note 4, but didn't get it because at the time, I didn't really need a phone. I'll need one for college next year, so yeah. Another thing is that I think the S-Pen would be really helpful for essay writing on the go. If there's a realistic reason why I care about the S-Pen it's that. For the speakers, I thought the one on the Note 5 was superb, especially with headphones. I do not know the luxury of front-facing speakers, though.
Taking my lack of care for the Stock Android experience and timely updates into account, would you still recommend the 6P over the Note 5? I did say I am going to get the 6P, but I keep looking back at the Note 5 :/ I just think it's the phone I want, but so many people are saying the 6P is gonna be great even after years, but the Note 5 would lag or something.
Well, again, it's all a matter of use case scenario. Different things matter to different people. If the following sounds sarcastic or condescending, please don't take it that way, I'm being on the level: If you don't care about the timeliness of updates, and don't care about a cleaner, leaner running OS that makes inferior hardware perform better "real world" than superior hardware, then I suppose there isn't really a super compelling reason to push you towards the Nexus over the Galaxy intrinsically.
But on the other hand, I didn't really hear anything in your reply that would really explicitly commend the Galaxy to you either. What kind of use case would you have where Touchwiz would be the more conducive version of the operating system? Would you really use S-Pen all that much? What Samsung specific software would you really need/want that doesn't have a Google or universal 3rd party equivalent?
These are the kind of questions you'll want to be asking yourself before you buy.
Also, are you putting your phone in a case or carrying it "naked"? If in a case, the vulnerabilities of glass vs metal aren't so much of an issue, but neither is the cosmetic appeal of glass vs metal. If you're not going to use a case, then you'll need to be more careful with the Sammy than the Nexy, and even if there is not a break, just scuffs and scratches will probably have a more long-term negative effect than with the metal Nexus.
The thing I worry about is that while you might not care so much about timely updates now, you might down the road, especially if/when there's another "stagefright" or "heart bleed". Or if Android N or Android O have a completely refreshed cosmetic that you really like, it's not like iOS where you'll just get it. It'll be a really long wait for something that when you finally get it will most likely still look way more "Touchwiz" than "Android".
You could always install Google Now Launcher for a pretty good approximation, but now you've added yet another layer of software on top of two or three layers already, and with each new layer, not only do you ask more of the hardware, but you also introduce the possibility for more bugginess. On the other hand, if you get a Nexus, and you get bored with stock Android, you can always install a 3rd party Launcher and customize things how you want. Yes it adds a layer, and yes you can do the same thing with the Sammy, but it's a matter of adding a layer to a layer vs adding a layer to multiple layers.
Also, two quick points you made I want to address:
1) I'll bet that not a lot of Note 5 users will particularly notice performance issues with their Note, especially in the early going. No, it seems that the disparity is really only noticeable when you've actually got the two side-by side. So I think it's one of those "off-white looks white until it's next to white" kinda things. Now on the one hand, that may take the teeth out of my "Nexus performs better" charge for you. But on the other hand, it also disarms the "I have a Note, and it works fine" voices as a refutation of the claim. Side by side reports favor the Nexus in spite of the spec sheet. And it makes perfect sense.
2) I'm also not saying any of this as a complete outsider looking in. Up until about three or four months ago, I had spent the past year and a quarter rocking a Galaxy Note 3. My wife had an S4 at the same time. I spend a good five to six months of that time checking daily for word of the Lollipop update. It's actually how I came to frequent the Mobile Nations sites. And when it finally did come....let's just say that I chose to use Google Now Launcher. The latest, greatest, safest, cleanest software IS important to me, so that whole experience created a "never again" feeling for me when it came to Samsung. I wouldn't go so far as to say I "hate" Touchwiz. I mean, it works okay, and it looks okay. I just hate how oppressive it is and how it stands in the way of those of us wanting a pure or "pure-ish" Android experience from having it.
Oh, also, I almost never used S-Pen. A lot of people find themselves not really using it. And the only Samsung proprietary things I regularly used were S-Health (which has a viable Google equivalent), and the mono audio widget (so I could listen with only one earbud in). That sucker is the ONLY real loss for me moving away from Samsung. Well, that and the simply breathtaking displays.
So, for what very little it's worth, I guess I'd leave you with this: if you can find an actual use case for having Touchwiz - something unique about it that will actually benefit you in the real world, or if after seeing a Sammy screen there's just nothing else that will do it for you - a sentiment I can actually appreciate - or if you're just so in love with the look and feel of Touchwiz and/or the physical look and feel of the phone and/or are so turned off by the stock material design aesthetic of Lollipop/Marshmallow, and/or the Nexus's weird camera bulge that it overrides all else, then yeah, get the Samsung! You will most likely love it!
Otherwise, this is where my recommendation of the Nexus comes in. The advantages to the Nexus are super practical, and if you don't really have a good use case for the Samsung (which it doesn't really seem like you do), then why deprive yourself of the Nexus perks? Even if you don't care about them now, you may care about them later. Or heck, even if you never ever care about them, you still have them and having something you dont care about is much better than caring about something you don't have - especially as the inevitable next wave of high profile Android exploits comes crashing down upon us again. And besides, they're less expensive. And the camera experiences are very competitive (it's even been argued that the Nexus is better - though I personally am not prepared to take a side there). And you may be the only guy in your circle to have one. Very unlikely with a Sammy.
Wishing you all the best! Let us know what you end up doing!
Cheers!