There are several ways TouchID is superior and several ways FaceID is superior. Hopefully some day we will get both. For me I find TouchID much faster for my typical use case. When I pick up my iPhone (say out of my pocket) I naturally grab it and place my thumb on the button and unlock it while i'm still moving it to view. It is unlocked well before it ever needs to see my face. With FaceID you can't do that, so even if the unlock process itself can be faster the FaceID - the overall process for me is slower in most cases. It was really frustrating to me.
Also while FaceIDs false positive (works when it shouldn't) rate is better, I found its false negative rate (fails when it shouldn't) to be much worse. I no longer have a FaceID iPhone, but my iPad Pro 11 drives me crazy with "camera blocked", "face too far away", or just doesn't work especially in low light situations - like using it in bed at night. Yes I know touchID has issues when your hands are dirty, or damp etc. - but for me that is a known use case and happens far less frequently then using it in low light situations.