While I generally have a positive experience, my biometrics just never seem to play nice! Iris' works maybe 25% of the time with or without glasses, and I've had it re-scanned too. I always just go straight to fingers. Yesterday, it couldn't read my right fingers, nor my eyes. When I used my left fingers, it took maybe 3-4 tried before it finally went through! My travel companion has a 100% success rate on iris lol.