It's an amazing phone. I've been an Android purist for years, but I finally had it with the lack of consistency between devices and lame slow updates from my fave device makers.
The experience is way better than previous iPhones I've used (one for work, friends' and family's). 3D touch is hard to justify as something you'd want or need until you play some games with it and it immediately makes sense. I have a lot of fun dicking around with music apps with 3D touch support as well. I can get all kinds of vibrato and other note control with it that makes music fun actually long term fun.
Camera experience is awesome. I've been taking great shots usually first try and it launches hella' fast. Live photos seemed super dumb at first, but I actually love it. Catching a funny look on my girlfriend's face after a photo is great. I've made some gifs from live photos a few times that were fun to share with coworkers (working remotely - shared some snow gifs).
I use a Macbook for work currently and it pairs with that great. There are a number of apps I like using with both. I've got Parcel for tracking packages going on both, can answer my phone on the Macbook, see my txts on my Macbook (without any ****e software) and I've really been digging Airdrop for large'ish file transfers with friends and colleagues when I need to get it over to them in a pinch.
Customizing my phone is not fun for me anymore. I've got desktop PC builds for that.
I just haven't felt like an Android phone has been a complete thought lately (I really did love my HTC One M7).
The iPhone 6s (maybe the 6 as well?) do have some decent water protection. Worth a thought. Not a fan of iPhone durability when it comes to drops. So I got the best insurance I could get for the phone. I dropped my HTC One on concrete several times and held together without a problem... but that raised glass freaks me out on iPhones.
I feel like I might be rocking this phone for quite a while.

It's a solid phone and I highly recommend if you can get a free 128 GB (what I've got), definitely go that route.