I&#x27;ve also gone with Spark, after looking into the bunches of iOS mail clients.  But I&#x27;m jaded now.  Sparrow was independent, and good, and got bought and shuttered.  Mailbox was independent and good, and got bought and shuttered.  Spark is independent, and very nice, but it&#x27;s free, and it&#x27;ll get bought...and shuttered. :(<p>I like Google Inbox a LOT, but it doesn&#x27;t have a unified mail interface, and if a million people don&#x27;t use it every day, it&#x27;ll probably get shuttered like Google Health and Reader did...<p>I&#x27;m just saying, don&#x27;t get too attached to your email client, especially if it&#x27;s not a profit center for the company making it.<p>Server-side access is what&#x27;s needed in order to do push-notification based email updates, which is an important feature for me, and having written that code once or twice, I&#x27;m totally okay with that.