Hopefully others will chime in so you can get some varied input, but, until then..

Anytime I hop on a friends apple computer I hate the universe. It's "so simple and intuitive" to the point that if you want to do anything it's complicated and nonsensical. Probably, if I spent a week using a mac, I'd get over this, but that's besides the point-- as it stands I hate macOS. With that being said, I love iOS. It generally just works, the use of the single main button is actually really intuitive. The camera on the SE and beyond is legit. But, yeah, just go check some iPhones out at a mac store.

As for size, that's another reason I went with the iPhone again. There just isn't much in the size range of the SE that is comparable. Even the standard size 6 is a small tablet-- but some people love it, so again go check them out at the apple store. Remember that you'll have to put this thing in and pull it out of your pocket though. I have a desktop with dual monitors, I have a laptop, and I have a phone. I suppose if you only were going to have one of these three, a tablet sized phone makes sense.