Worth what exactly? What do you think the X could do better / smarter / faster / "cooler" than your "very old 6S+"? If you're unsure rationalize it. Take 5 minutes and write a Pro and Contra list. If you find more pro points, buy it. If not, you're good with your 6+ ;)

PS: I'm saying that from a perspective of owning an iPhone 5 and I stood in front of the X. I tried it out and found out that it doesn't excite me much when holding it in my hand. So, my decision against it was pure gut and intuition - contrary to what I suggested to you ^^. Yes, the 5 is pretty slow (and probably the 6 as well by now) but it works for what I'm doing (camera, browsing, some apps)

had 6s+, bought iPhone X - no regrets! It's really amazing - perhaps subjective opinion but it really feels great when I'm using it...

📲 phone and screen size is much better/optimal vs Plus models
➖ the notch doesn’t bother me at all
🔮 #FaceID is pure magic and super fast... 95% I don’t even notice it’s there
😍 v. pleasant experience - love using it

I'd say that the expense is the biggest concern. I bought one for my wife opening day, and she likes it, but I'm going to take my time to upgrade.

The phone is almost worth it. It just depends on if you want the latest best thing.

iPhone X is the first phone that excited me and made me wanna buy immediately since the iPhone 4 came out. I'm on a 5SE now which I bought immediately because my 5 was getting old and clunky (upgraded from 4 because it was slow) and the 5SE has the same internals as a 6S but with a better sized screen.

Have held the X in my hand. It's waaaaay too big I'm hoping they come up with a smaller version. Using it however feels much nicer than using my 5SE. You can really tell that iOS11 was actually made with the X in mind.

That said, I'm holding out for the 2nd generation at least. OLED screens are not quite "there" yet and Apple has a history of quality issues on first generation with new technology products.