Choosing Your VIPs
It's distasteful to talk about in public, but let's be honest: there are e-mails that can wait, and there are e-mails that can't. What determines the split? The sender, of course. With the introduction of iOS 6, Apple has added a new VIP system that enables you to select and label certain people in your Contacts list to be more important than the rest. People like significant others, bosses, children, and so on. From a mail perspective, this is hugely important when it comes to seeing important messages first.
Much like the arrival of a text message, you can allow any VIP that sends an e-mail to an account established in your Mail app to have their message show up on your lock screen. Think of it as a "high priority" alert. While in the Mail app, you'll also get a new VIP inbox, where you can sift through messages sent only from folks who you've deemed highly important.
Password and Multiple Account Management
Look, you're a popular person. There's no need to feel ashamed about having eight e-mail accounts. (At least, you can keep telling yourself that.) All jesting aside, there are a few snippets you should know about having a cadre of accounts within Mail. For one, the notification bubble on the Mail icon-which represents a view of how many unread messages you have-shows the sum of all unread e-mails across accounts. There's unfortunately no way to force the icon to only show unread message counts for a specific list of accounts, which might not bother those who go to great lengths to maintain a "zero inbox" in their most used account.
The importance of carefully selecting which account is your default, but changing from one to the next is fairly simple. While in the Mail app, just tap Inbox → Mailboxes in order to pull up a list of your accounts. I recommend naming them with care. If you have more than a couple, using just your name, "personal," or "work" may not be descriptive enough.
For now, Apple has no feature that allows you to lock specific apps or e-mail accounts. Once you're through the optional lock screen password-which you established in Settings → General → Passcode Lock-you've access to everything. This is particularly troubling when you need to hand your iPhone off for a work presentation, but would rather your nosey colleagues not "accidentally" read your e-mail or spot any personal push notifications.
Tip:
One idea is to switch lessimportant accounts to manual fetch, so you aren't distracted by push notif ic ations (and a surging unread count) from accounts that are not urgent.
To date, there's no app in the App Store to remedy this, but jailbreakers have an option. A few, actually. FolderLock, Lockdown Pro, and Locktopus can be found in Cydia or BigBoss repositories, and all are priced at under $5. These apps allow you to enable very specific locks for apps and content, and again, my suspicion is that Apple sees the light here and integrates similar functionality into a future iOS build.
S/MIME (Secure/Multipurpose Internet Mail Extensions) is one of the more advanced security features that most common folk will just gloss right over, but for those obsessed with keeping track of signed messages (or those that have this requirement due to the sensitive nature of their work), it's a great feature to tap into. Apple has enabled support of this by default within iOS, and you'll need to dig into Settings → Account → Advanced for each e-mail account in order to enable it on each account. From here, you can opt to receive signed messages and sign them yourself, but you'll need to procure a certificate elsewhere, first. Once in possession of that (VeriSign's a good place to head for that), just e-mail it to yourself and have iOS install it.
Note:
Jailbreaking isn't for the weak spirited, or the cowards, but plenty of information is out there on Google for those who want to dive in. It voids your warranty, though, so you're operating at your own risk!
Conclusion
Although the iPhone has "phone" in its name, it's clearly more than that. It's an e-mailing machine, and iOS 6 has added plenty of new features (VIP lists, for example) to highlight this aspect. Simply managing the influx of information and notifications is a job in and of itself, but Apple's notification options allow you to surface e-mails from the people most important to you.
Google finally succeeded in bringing a native Gmail app to iOS, and while it's far from perfect, it does give avid Gmailers access to the subtle extras that make it so compelling. A native Gmail app has kept many on Android; the addition of this app into the iOS ecosystem could be a great reason to switch. Managing multiple accounts-and perhaps even multiple tools for sending messages-is tricky but worth the effort.