Lark vs SleepTracker

Silent alarm clock and sleep sensor for iPhone/iPad. Designed with Harvard sleep expert and pro sports sleep coach. LARK wakes you silently and gently- you’ll even snooze less. The LARK wristband (lovingly known as wrist pajamas) uses an actigraphy microsensor to detect your unique sleeping patterns. No syncing, it automatically shows up on your phone.
SleepTracker’s SmartStart Technology monitors your sleep stages throughout the night and then uses that data to determine the exact moment when you should be awoken helping you feel refreshed and energetic. SLEEPTRACKER also comes with the most comprehensive sleep software available allowing you to see how you slept, ways to improve your sleep, and your overall sleep score.