I use Face ID on my iPhone X and Touch ID on my iPad Pro 12.9. I find they both work fine, I have no problems with either. I believe that Face ID is a bit faster, and I truly believe that it opens security apps (like my bank app) faster. It is also handier to use once you have unlocked the phone, especially when opening an app one handed. With Touch ID you have to shift you hand to a position that increases your chances of dropping the phone, while with Face ID you just hold the phone up to your face.