The whole point of Apple's AirPrint is to make printing something that just works -- no driver installation, no setup, no adding printers. If they're available, they're simply there, ready to use. In fact, the AirPrint technology works just as promised, but when we reviewed various products to extend AirPrint to existing printers, we discovered that iOS apps aren't always AirPrint savvy, causing all sorts of gotchas.
If there's good news, it's that the Android world is in much worse shape than the iOS world. Android has no built-in printing technology, so apps don't expect there to be one. When you do enable printing from Android via a product such as EFI's PrintMe Mobile, the results will be mixed. Printing will be available in some apps and contexts, but not in others.
What to look out for in iOS and Android printing
Since iOS 4.2 in fall 2010, apps have been able to incorporate the AirPrint APIs to enable printing without drivers. In fact, Apple closed the loopholes in iOS that some apps used to print: It's AirPrint or nothing.
The iOS development standard is that printing is made available through the Share icon button (the one of a curved arrow coming out of a rectangle), which apps also use to mail, tweet, and otherwise share contents using iOS's built-in sharing APIs. But not all apps use this iOS standard.
For example, Quickoffice -- one of the leading office productivity apps for iOS -- doesn't support Share, nor does it make printing available elsewhere. In other words, you can't print from this mainstay office productivity app. Ditto with Documents to Go from DataViz -- it doesn't implement the printing APIs.
Ironically, Apple's own iWork suite -- Pages, Numbers, and Keynote -- doesn't follow Apple's own convention for making printing available. Rather than have the standard Share icon menu, they use the Settings icon menu (a wrench icon) as the venue for providing printing. But at least you can print from these productivity apps once you know where to look.
Likewise, Byte2's Office2HD productivity app uses the same Settings menu to provide access to printing. Office2HD is so far the only iOS office productivity app that supports standard Microsoft Office revisions tracking for changes made in iOS, by the way.
When you print in iOS, you may be puzzled by inconsistencies in the Print popover. As they say in Silicon Valley, it's a feature, not a flaw. Rather than list all possible options and gray out those unsupported by the current app, printer, or document, the AirPrint popover hides those not relevant. For example, if an app is page-oriented, like Pages or Office2HD, you get the option to select a range of pages to print. If an app doesn't support the concept of pages -- such as the Safari browser or Mail email client -- there is no option; the whole "document" prints, and you have no choice about it as you would on a Mac or Windows PC.
With EFI's PrintMe Mobile for Android, printing works much like it does in iOS. PrintMe Mobile appears as an option when you tap Android's Share button, when you click to view or download an attachment in Gmail, and in other places where you're able to choose an app to complete an action with a file. Unlike in iOS, however, where some apps allow you to select a specific page or pages for printing, printing with PrintMe Mobile for Android is always an all-or-nothing affair: You can choose which entire document to print, which printer, the number of copies, and whether to print one-sided or duplex. That's it.