The keyboard helpfully offers command keys like Windows and Command not available on the iPad, as well as cursor (arrow) keys. But the keyboard is awfully large, obscuring much of the window. The iPad's keyboard can take up half the screen when in landscape mode, but apps adjust their display to reposition the text being worked on, so it usually remains in focus -- not the case with OS X or Windows apps in Parallels Access. Plus, OS X and Windows use menus and formatting bars at the top of the screen, far from your text. That works great on the large canvas of a computer monitor, but on an iPad screen half taken by a keyboard, it's impossible.
The onscreen keyboard in Parallels Access obscures the text you're working on and puts most menus out of sight.
Drag operations are difficult to accomplish too. This is an iOS issue -- its gestures don't support the kind of dragging you would do for a window, resizing an element, moving a file, and so on. This is a problem when using a browser in iOS as well: Draggable items on a Web page, such as in a form or content management system, don't drag in iOS, as there is no "tap, hold, and drag" gesture. But when you're using a PC or Mac, you realize how fundamental that action is to a mouse environment and how it isn't used in iOS.
Despite the zoom-in pointer, selecting items is difficult, especially within text. And screen display of text sometimes flickers as you try to select text. No question: The mouse is more precise than the finger.
Even with Parallels' tricks, the apps are still OS X and Windows apps, and they're simply not designed to run in a touch environment like iOS.
When a connection to Parallels Access is established, your PC or Mac is forced into 1,024-by-768-pixel mode, your windows are rearranged and resized; most are expanded to the full screen. (They're put back to their original sizes and positions when you disconnect, and your screen is returned to its previous resolution.) You might try to trick Parallels Access by changing the resolution of your computer's desktop via the OS X Displays system preference or Windows' Displays control panel. This will indeed make the larger screen resolution appear on your iPad, though it is shrunk to fit the iPad's screen (rather than be a scrollable window), so the contents become too small to use. That's why Parallels Access changed the resolution in the first place!
If you switch out of Parallels Access on your iPad, such as to answer an email or use the browser, your connection is interrupted; this is perhaps meant as a safety feature for an unattended computer. On the PC or Mac, you get a full-window alert asking if you want to disconnect. (Obviously, someone else would need to see the message and decide whether to disconnect the connection, as you're not at your desk to confirm that action). If you switch back to Parallels Access, your computer's screen resumes where it left off.
Despite its innovations, Parallels Access provides just a window onto your PC or Mac. That window is a real barrier to working with the contents inside. I can see the value of having a VNC app for emergency access to a PC or Mac, such as to send yourself files you didn't make available to your iPad via a cloud service or through iTunes syncing -- assuming you can get someone to turn the computer on and sign in (and you use a password on your computer). But I can't see spending $80 per year per computer for the privilege, which is what Parallels charges.
Parallels Access is interesting technology that shows what engineers can do when they get creative. But it also reminds me that an iPad isn't a computer and doesn't need to be one. After all, if the reason to get an iPad were to run Windows or OS X, you'd use a lightweight PC or Mac laptop instead. And there are desktop-as-a-service apps like CloudOn that provide cloud-based Office environments to the iPad that work reasonably well when a native iPad app like iWork or Quickoffice won't do.
I often hear from virtualization vendors how they can satisfy IT desires for a common platform by providing virtual Windows desktops to iPads and other tablets. (Office is not the only reason people use PCs.) But these tools, even when done elegantly like Parallels Access, forget that people don't by iPads to run Windows (or OS X). They buy iPads to run iOS apps and use that environment.
In trying to bridge iOS with OS X and Windows, Parallels Access underscores the basic reality that an iPad is great at being an iPad, and it should be used that way.
This article, "Parallels Access shows why an iPad is a poor PC or Mac," was originally published at InfoWorld.com. Read more of Galen Gruman's Mobile Edge blog and follow the latest developments in mobile technology at InfoWorld.com. Follow Galen's mobile musings on Twitter at MobileGalen. For the latest business technology news, follow InfoWorld.com on Twitter.