HP's TouchPad was an okay product according to reviews, but it lived a very short product life because consumers showed a hearty appetite for Apple's tablet-leading iPad. Now, many are asking if Apple's iPad will ever have a worthy competitor.

At the moment, however, there's no competitor directly on the horizon ready to challenge the iPad.

The reason is simple: Apple has advantages that tie consumers together beyond a basic love of the iPad.

There's Apple's iTunes, and the way Apple's iPad ties in user apps and other tools seamlessly from device to device. Once Apple claims an iPhone user, or a Mac laptop user, the company has an advantage with its tablet, since everything from apps to experience is seamless with its other products and services.

So while HP's TouchPad got okay reviews, Apple's advantage is now far greater than the product alone.

So far most other tablets are offering a hardware solution or a software solution, but not both, said Rhoda Alexander, director of monitor research at IHS iSuppli, in an interview with CNN. Even if each one is good on its own, it takes work to put them together. Apple did that beautifully.

Consumers are gobbling up HP's TouchPad now that the company has announced it's discontinuing the device and support for it, while slashing the price to $99, but that's just fire-sale opportunity. Apple's iPad sells for $400 and up depending on the model, and the TouchPad launched at $499 and up just seven weeks ago before it became a one-for-the-ages product flop.

To thrive in the tablet space, $99 won't get it done.

Thus, for the moment at least, Apple's industry-leading tablet advantage should only grow wider as the company nears a late 2011 or early 2012 launch of its newest iPad, the iPad 3.

Interestingly, though, the company with the best chance at launching a competitive product at Apple's iPad may be online retailer Amazon.com.

Amazon is fast becoming a technology company based on its Kindle e-reader, the industry leader. The company is also said to be developing its own tablet, based on Google's Android operating system. Amazon has Appstore for Android and it's got trusted, valued relationships with Kindle customers.

That strength is the closest any company has to Apple's advantage. Amazon is among the world's most visited and used Web sites. Recent statistics showed, for instance, that one of five adult Internet users in the world visited Amazon's site in June. Customers have Amazon accounts just like they have iTunes and Apple App Store accounts. Many also use Amazon's Kindle bookstore, which works nicely on tablets.

But even though Amazon shapes up as the competitor most capable of competiting against Apple's iPad in the tablet space -- the company's plans still haven't been made public. For now, it's wait-and-see, with Apple clearly in the leadership position.