Crazy in-depth review of Sparrow for the iPhone, which was just release today. I downloaded the app and have to say, it's impressive. The UI is fantastic and snappy. I highly recommend it to anyone who uses Gmail (or even iCloud). One thing to note though, there are no push notifications. For some this may be a deal breaker. I've recently reverted to "pulling" email to eliminate distractions, so this hasn't been a big deal for me.