My last iPhone was iPhone 5 so I'm new to Touch ID. I've heard a LOT bad news about Touch ID from news sites, youtube and even my friends. But when I first tried I was blown away. It's super fast and accurate. I scanned 4 fingers (two thumbs and two indexes) without any problems. The unlock speed is even faster than "slide to unlock" way. I guess it's because When I press the home button the sensor already started to scan my fingerprint and I can't even see the lock screen clearly before it disappears. And because I registered my finger from many angles including the flat angle and common used slope angles. No matter how I press the home button it always recognised my fingerprints. I've done a test and figured out that it only takes about 0.3 seconds to recognise, sometimes you feel it's slow is because the UI lags. I'm really impressed with new Touch ID on iPhone 6. I only got this phone for about a week so I can't tell if the sensitivity drops from time to time. But we will see.