I have to admit, I sorely underestimated how long it would take the rest of the tech industry to respond to the iPad in any meaningful way. Two weeks before Apple finally moved the device from the Strongly Rumoured list into the Holy Jumping Jesus! roster, any number of companies were showing off their own 10in tablets running Android on Tegra processors.

I was sure that half a dozen challengers would be released in time for the 2010 holiday season. Instead, the industry collectively behaved like one of those chess players who makes a move but then keeps their finger on the piece and mutters, “It’s still my turn… I haven’t gone yet…” while they obsessively continue to eye the board.

A couple of weeks ago, the first credible alternative to the iPad finally arrived in my office. The Motorola Xoom, like the iPad, is a 10in tablet running a mobile OS (Android 3.0). It’s a nice piece of gear. It’s no threat to the iPad but using it helped me to understand what makes the iPad work.

The iPad’s size and shape are shrewd choices. The Xoom is just as big as the iPad, but the display’s aspect ratio is widescreen. That’s great for watching widescreen movies but it doesn’t really lend itself to any other kind of media and I almost never wanted to use it in portrait orientation. The iPad works just as well in portrait or landscape.

The iPad is defined by its OS and software, not by its hardware. It’s not hard to produce a physical device that’s as good as an iPad. You can nitpick about the differences between the Xoom and the iPad – the Xoom is likable where the iPad is lickable – but the truth is that Motorola’s tablet is well built, totable, and very satisfying to hold.

Android 3.0 is a different story. Google has a consistent theme with all of its software: it’s serviceable but lacks that final round of clarification and fine-tuning that Apple seems to put into everything it does.

A tablet has to seem like one device, not like a computer that runs dozens of different apps. Using the Xoom, the one thing I missed about my iPad above all others was the sense that the hardware, the OS, and each of the two dozen or so apps I rely on were designed to work together seamlessly. Even when I stuck to Android’s built-in apps, I felt like I needed to relearn some basic skills and familiarise myself with new quirks every time I switched tasks. At times, it seemed like Google’s in-house developers weren’t particularly aware that they were developing an app for a tablet instead of a notebook.

Google doesn’t understand that it has a responsibility to behave like an evil megacorporation that wants to crush all opposition. Google has many of the best and most popular web apps. Everybody uses Google Reader to manage their daily blogs and news, and thousands of institutions have standardised on Google Docs. So when I pick up a tablet that runs a Google OS and launch a Google-created web browser and navigate to a Google web app, I’m expecting a spectacular experience. Instead, Google Reader identifies the Xoom as a mobile device and serves up the stripped-down smartphone edition. You don’t even get the standard full web edition. Seriously.

Apple may be a tyrant, but when the company exerts control it also imposes order and improves the overall experience. Google can’t even be bothered to make its own web apps work well with its own OS. With an attitude like that, they’ll never grind the huddled masses under their iron-studded boot heel.

The iPad’s content advantage is often overstated. My biggest disappointment with the Xoom was the paucity of apps. But I wasn’t hoping to find 100,000 titles in the Android Marketplace: just eight or nine quality titles. The fact that I could get the Kindle app, for instance, meant that the Xoom was as good a book reader as the iPad.

The lesson here is that while Apple needs to continue to innovate the iPad’s hardware and software, it also needs to maintain a good relationship with developers and content providers. The iPad isn’t a Magical Device. From my perspective as a user, it’s a great tablet that runs the two dozen apps I need and can read a wide variety of consumable content. The iPad will by no means maintain an exclusive on those things. When a company like Amazon decides it’s making enough money from 100 Android devices that it can ignore the three iOS ones… watch out.

A low price is penance for a multitude of sins. I couldn’t recommend the Xoom to anyone. It costs more than the iPad and it doesn’t do anything better. Barnes & Noble’s Nookcolor ebook reader was an eye-opener, though. It’s a slick ebook device and, hidden underneath the reader app, it’s a 7in multitouch colour tablet running Android.

There’s a hack for wiping the device and turning it into a full-featured Android 3.0 machine. All of those complaints about the limitations of a 7in tablet and Android get swept under the rug when you consider that you can buy the Nookcolor for just $249 (£154).

If I see any threat to the iPad’s supremacy, it’s the £439 entry-level price. No other maker can touch it but it’s still the price of a computer, not a consumer device. Put another way: it’s the difference between A Very Nice Christmas Present and ,“This has to count for your birthday present too… and you can’t come with us on this year’s family holiday, either.”

What’ll happen if the market is flooded with perfectly decent £150 Android 3.0 tablets, and a lot of new money and users enter the Android Marketplace? I wonder.

It’s important to remember that the iPad’s dominance of the tablet market isn’t the result of Divine Ordinance. There are reasons why the iPad works as well as it does and there are reasons why other devices could one day do just as well. If Apple overlooks either one of those things, it’ll quickly become apparent that Apple never had a lock on the tablet market… just a two-year headstart.