I just went through the same decision process myself. In the end, I chose the 8+.
Why? Because the X, while it claims to have a larger screen, it actually doesn't. It's tall and thin with the giant notch in the top. So when you are watching a movie, you lose that area with the notch, and most movies are encoded in a 16:9/10 aspect ratio, so the X's screen ends up cropping things or wasting space with that letterbox view. The notch is a waste of space. The X has a top bezel, they are simply putting part of the screen there to make it look like it doesn't. It's an optical illusion. They would have been better just having a tiny top bezel and putting the sensors there and maybe a notification bar. Instead they extended the screen there around the sensors making it look bezel-less, while wasting the parts of the screen that they put there. I would expect Jobs would have strangled whoever came to the meeting thinking that notch was a good idea.
The 8+, is wider and better for watching movies and viewing websites, less side to side scrolling because of the more common aspect ratio.
Second, was FaceID. It's slower, and when you are like me and half the time wearing a dirt bike or motorcycle helmet, faceID is useless. The fingerprint is faster and more versatile. Apple should just put it on the back like most Androids do, which would give them the edge to edge screen, without having to resort to FaceID and that ugly wasteful notch.
Third, price. Same CPU and internal specs, and the 256GB 8+ is $50 less than the 64GB X. That $50 you save buys a nice case, and gives you quadruple the storage.
The X looks good on paper and it's certainly pretty, but as far as "usable" screen size goes, its a smaller screen, the phone isn't any faster, it costs a lot more and so I went with the 8+.
The Pixel2 XL is my ideal phone, but Google dropped the ball putting a crappy LG screen on it, so of the other phones out there, I settled on the iPhone.
I have an Essential, brilliant hardware and materials that beats even the X, but they can't seem to squash the software bugs, ironic as it may be that the CEO and Founder is Andy Rubin, the guy that created Android... LOL Disappointing because of the premium specs and titanium and ceramic construction, coupled with the fact that it had a true edge to edge screen without a giant notch months before the X did...
Samsung, too bloated with carrier and Samsung crap and I hate curved edge screens... can't protect them properly and they are just begging to be dropped and cracked.
OnePlus 5T, amazing phone but AT&T won't recognize it officially and so no Wifi Calling, VoLTE and some other carrier functions...
So that left me with Apple this time around, and I went back and forth for weeks between the X and the 8+ and in the end, the 8+ was the clear winner for me. No notch, no useless face ID, bigger screen when it comes to actually using the phone, lots more storage and still cheaper without sacrificing any performance.
The only true advantage I can see the X as having, is a couple camera tweaks... but the 8+ has such a good camera, that most people couldn't spot the differences if you didn't have them side by side with someone pointing them out.
