I have a galaxy s8 plus, the non American version. All the American version phones with Snapdragon processors are rubbish. It is smooth but the screen is elongated so may take some time to get used to.
I also rocked a note 4 (again the non American version) and it was very good. I'd actually prefer it to my s8 because of the instant battery swap. Also provides easy screen reduction for one handed catching. It's not waterproof so no go in the rain however.