Honestly, please tell me what the S6 better than the OnePlus One ?
For me, it's the reasons below. Listed in no particular order. Just the reasons that come to my head:
1) Headphone jack on the bottom - It sounds silly, but this is a big deal. I hate the headphone jack on top of the OnePlus. I like putting my phone into my pocket upside down, and the headphone jack sticking out from the top is really irritating (especially for such a large phone). And even when it's out in my hand, having the cords sometimes dangle in front of the screen is cumbersome. This is a device I use every single day; I put it in and pull it out of my pocket a countless number of times in that single day. This is more a big deal than it sounds.
2) Smaller device - Don't get me wrong, I appreciate what a larger device brings: larger screen for gaming/browsing/videos. Larger battery. But there's something to be said about easier one hand use and pocket-ability. Seriously, the OnePlus is large. It's absolutely manageable, but if I'm honest, it can sometimes be tight and/or uncomfortable in my pockets (especially when getting in and out of a car, for example), and it can sometimes be unwieldy if I'm trying to use it with one hand (say while riding the subway or something). I miss the feel and comforts of a smaller screen/device.
3) TouchWiz - From what little of TW I've used and from what videos I've seen, I'm actually warming up to TW. I think some of their extra features are worthwhile, and I actually think TW plays beautifully with Material Design. The colorful-ness of TW makes a lot of sense now coexisting with Material Design. As you already know, I actually love Cyanogen, but I'm also excited about TW's extra features and touches. (I also think it's a helluvalot better than what I've seen of Sense. Ugh, can't stand the way Sense handles app switching. Tiles? No thanks!).
4) Camera - This is the one area I think the OnePlus falls short on, and I've always said so as much. Back on my iPh6, whenever I'd want to take a photo, it was a one snap deal. With one snap, I knew 99% of the time, I got a good, clear, clean photo. With the OnePlus, I now snap 2 or 3 times just to ensure at least one of them comes out well (and inevitably, of the 2 or 3, one of them is almost always blurry). The OnePlus camera is good, no doubt, but it isn't as quick and/or reliable as the iPh6, and presumably as well as the S6. I really miss that sort of reliability for my smartphone camera. Also... double tap home screen to launch the camera in under a second? Victory.
5) Fingerprint scanner - Speaking of that home button, I'm excited for Samsung's finger print. Let's face it, double tap to wake on the OnePlus is not reliable. Sometimes it flat out doesn't wake when I double tap it. I've tested out the S6's home button, and the finger print scanner is fast and reliable. I would even go as far saying it's a hair faster than the iPh6's.
6) Samsung - I respect OnePlus and like what they're doing, but I dislike Cyanogen's CEO (he's a d*ck). I know this is neither here nor there at the end of the day, but I just like what Samsung is doing. Never mind all their hyperbole and Apple-smear campaigns (some of which, in my humble opinion, I think are brilliant), but Samsung is doing exciting things in the tech sector. Yeah, sometimes they lose control and spread too thin and try too hard, but by doing so, they also venture into exciting places. Basically, I feel like Samsung deserves my money more than OnePlus at this point. Again, OnePlus is young and exciting and pushing boundaries (especially pricing-wise) of their own, and I look forward to what they unveil with the OnePlus Two, but for now, I'm comfortable giving Samsung my money.
7) Design - The S6 is one of the most gorgeous looking (and feeling) phones. The iPhone 4/4S was my favorite phone design. 'Nuff said.
8) Quick Charge/Wireless Charging - What I lose in battery size, I gain in ease of charging. 10 mins = 4 hours? That's really amazing when you sit down and really think about that. And wireless charging, I think, will be great. Allowing the device to top off when I'm not using it is going to be invaluable. Hey, it's sitting idle on my desk at work/home when it's not being used anyway, so why not put that idle time to better use? GSMArena put up updated S6 battery results, btw, after they got the final software build. Look it up. The results are much much better.
Um, I can probably think of a few more things, but I'll leave it there for now. Whether or not someone else agrees this is worth the markup in price, that's obviously up to each individual. I'm ready to pay that price for what I'm getting with the S6.
Lastly, I want to be clear, the OnePlus is probably the best smartphone I've ever own to date. Much of what you've applauded it for in this thread, I agree with.