Got a G955F (Exynos) a week ago, replacing my OnePlus 3.
The OnePlus 3 was (and still is, sold it to my roommate, he upgraded from some 2014 Galaxy Grand Neo or some s#%t like that

) an awful lot of phone for the money, especially with the AOSPA running it. Fast as hell, charging also fast as hell, and the thing made nice photos with the ported Google cam.
I wanted to switch because my previous phone was the Note 3, and after a year and a half with the OP3, I became... bored with it. First world problems. My issue was, using it one handed couldn't be done easily, no one handed mode, and couldn't use it two handed easily, too small for that.
So I went looking for a replacement. My first choice was the Mate 10 Pro, having Project Treble out of the box, that machine learning chip, dual cam, but after a week back and forth with my carrier, units not available, got sick of it all, and last Friday just barricaded an employee of my carrier in the store, dead set on not leaving without a new phone, but since the Mate 10 Pro was so elusive, I got the S8 Plus. Bigger (and better) screen than the Pro, thought performance on a 10nm Exynos would be good, microSD slot, headphone jack (!!!), wireless charging. Fast charging on the S8+ isn't as fast as the Mate's (I presume), I got spoiled by the OP3's stupidly fast Dash charge, the S8+ feels like a slow trickler in comparison.
I don't regret it, despite the fact I still haven't tripped knox and flashed the Oreo beta, which is a first for me.

1. Battery life. Somehow, despite the heavier feel of TouchWiz, despite the giant Quad HD+ screen, Samsung somehow manage to get me better longevity than the OP3 did. Screw me if I know how they pulled it off, but kudos for it.
4/10. (Had a ZeroLemon 10000 mAh unit on my Note 3, and until phones start lasting as much as the Note 3 did with the ZeroLemon, that grade will stay that way.)
2. Cameras... now this is a mixed bag. S8+ front camera has autofocus, 8 MP unit like the OP3, but the images are pathetically ugly for some reason. Lots of noise, off colors, and that beautification "feature" makes all of the above way worse. Google's cam barely makes better photos with it. Yes, my mug ain't exactly pretty, but the OP3's selfies were more realistic, while this cam can make images of my face that are a nightmare fuel.
The main camera, however... I think I like it, though I still haven't tested it properly. Low light shots are definitely better that the OP3's, but in daylight, with the Google cam, the OP3 delivered some SICK shots. Still have to test if the S8+ can deliver that too.
Front cam 4/10.
Rear cam 8/10 (so far).
3. The aforementioned screen... Another mixed bag. I like the size of it and the resolution, my first QHD phone. I'm running it in Basic mode, the OP3 spoiled me for sRGB, can't stand Adaptive display, ridiculously oversaturated.

Though maybe if I could get used to it... I am mentioning that because at work we have an iPhone X unit, also AMOLED panel, it has the vivid colors, but they're NOT over the top somehow, and puts the Basic mode on the S8+ to shame.
Then again, I haven't played around to calibrate it myself, maybe I'd be able to reproduce what I found on the iPhone... aaaaaaand, while still writing this post, I tested out the AMOLED Photo mode, and I think it's kind of what I found on the iPhone. Scratch my previous complaints.

9.5/10.
4. Performance. Having a Note 3 for 2 years, I know of TouchWiz lag, and it's way lower on this device. Still the occasional hiccup, but I got used to the OP3's hyperspeed mode, and at times it looked like the apps themselves couldn't catch up to the phone, and I have the same feel here too, sometimes. Other times it's pure lag, but not something that would make me flip.
9/10, since performance throughout and within apps is close to the OP3.
5. Design. Yes, the thing looks sleek, and since I wanna keep it that way, slapped a case and a glass screen protector on it. This is the least important part for me, as long as build quality is on point (and it's so on point I can't say a thing <3), and design is hidden behind protection anyway.
Of course, getting used to the stupid fast unlock with fingerprint on the OP3 makes me hate the position of said reader on this phone, but I can live with it, thanks to the iris scanner.
10/10 for build quality, maybe 6/10 for the questionable design decisions, especially Samsung's deluded decision on where a fingerprint is appropriate to be. Maybe they had to do it this way to slap the wireless charging on it, but I'm not an engineer, I'm a consumer, and I don't like the position.
TLDR: No regrets on buying this, would have returned it by now otherwise.