Smart phones running Google’s Android are outrunning Apple’s iOS-powered iPhone of late ¹ but, in the tablet wars, Android devices are so far behind the iPad they might as well be invisible. What’s up?

Time is one factor. Android spent several years trying to catch the iPhone and the iPad’s only been around for one. RedMonk analyst Stephen O’Grady expects Android will catch up sooner or later, but I’m not so sure.

That’s because there are deeper reasons for Android’s failure on tablets. The features that make Android preferable to iOS for many smart phone users aren’t as important on tablets. And Android is far behind on what makes iOS preferable on tablets in the eyes of most users.

Start with phones. Android surpasses iOS in notifications and by doing a better job providing what I would call personally relevant news more clearly and concisely with minimum fuss. That is stuff like Facebook updates, Twitter mentions, emails, text messages and the like. Not everybody cares about this kind of stuff but a lot of people see their smart phone first and foremost as a real-time communications terminal. And for that crowd, the notice and updates advantage is important.

Android also has a big advantage because it’s available on a variety of hardware. Want a physical keyboard, 2″ screen, 4.3″ screen, a yellow shell, a removable battery? Not from Apple. And, in turn, the variety of hardware almost inevitably leads to a greater variety of carrier choices, monthly plan prices and phone price points. There are even Android phones for prepaid, or pay-as-you go, plans, one of the faster growing segments of the mobile customer base.

Again, these advantages are not relevant to all smart phone shoppers but to many — and for those many the iPhone isn’t even in the game. Given that Android is outpolling the iPhone, one or more of these advantages must be pretty important — even decisive — to a large portion of the smart phone buying public.

But what about on tablets? There the situation is reversed.

One of the best and most popular uses for the iPad is watching video. On the iPad, you can pick from thousands of movies and television shows for purchase and rental in the iTunes store, streaming via the Netflix or Hulu Plus apps and a growing number of cable-related on-demand apps.

What’s the video situation on Android? As discussed endlessly, it’s horrendous, with no unified video store like iTunes and the “benefit” of device and carrier variety in this area exacting a terrible toll.

And speaking of hardware variety, the iPad actually has the advantage here with various features, carriers and colors (!) available at price points from $499 to $829. The Android Honeycomb tablet out thus far comes in one size, one price, and one color fits all. And not a very competitive price, either.

Finally, the app advantage of Apple’s iOS means a lot more when there are 60,000 iPad-specific apps and only 16 apps designed for Android Honeycomb tablets. On phones, the Apple advantage of 350,000 apps to Google’s 200,000 is much less critical. The 17th best app on the iPad is going to be a heck of a lot more significant than the 200,001-st Android phone app.

And that puts the iPad way out in front for as far as the eye can see.

Notes:

¹Let’s not get too worked about market share stats, the Verizon iPhone and all that. Some recent reports even show Android outselling iPhone on outlets in Europe like Tesco and Carphone Warehouse that offer both platforms. Can we at least agree that Android and iPhone have just about reached competitive parity? Maybe?