Samsung doesn't have this technology. Samsung has static image unlock - you can literally unlock the phone with a picture. When I say FaceID I don't just mean the unlocking part - but the technology powering it. Sure animojis doesn't look like much, but it is basically just a demo of what it can be used for. Other developers can do much more with it. Think of it like a Kinect (which sadly is dead on the console now) inside your phone.
As I said previously, FaceID might just be to unlock the phone - but the technology powering it can be used in games etc - if you have a quizzical look on your face siri can pop up a help file etc.
On performance - the S8 (which is the first Samsung that got a better cpu score than the iPhone 6S (3 generations ago now)) has performance issues and it cost a lot as well. So performance is an issue still. And by night and day I assume you are referencing the way android keeps the whole memory space of the app alive for multitasking that can impede the in focus app which means iOS has better performance.
Will be interesting to see the phone live.. in all fairness I am looking forward to the S.A. launch... to go and play around with the phone.