Motorola’s Xoom has been hailed as the most likely tablet computer to rival Apple’s iPad–the first with the goods to compete against the uncontested leader in this nascent but rapidly growing market, the Associated Press reports. After trying it out, I found it to be a great gadget that, in many ways, can keep up with the black slab from Apple. The first black slab, that is. Unfortunately, Apple said Wednesday that it will start selling a new, improved iPad next week, which will likely make it difficult for the Xoom to snag many users. The Xoom is well-equipped, with a large, vivid touch screen and zippy processor…