Android user here, but I've used an iPhone for a few days a few years ago while I was in-between phones:

It is so much more smooth. I think it can be closely mimicked by having a high refresh-rate display on an Android phone, but iPhone just feels so much more fluid and snappy. Haptics are night and day, too.

Really, the only reason that I didn't stick with the iPhone was because I wasn't really ready to make the switch. There were a few dumb design decisions that I couldn't really stand, but they're not dealbreakers for most people. I would say go for it - if you don't like it, Apple's return policy is pretty generous. I'm thinking about getting an iPhone as my next phone in a few years; Android is just disappointing and half-baked to me, anymore.