Lighter and Faster, It's iPad Air The new iPad Mini, left, and the iPad Air. The Air will have plenty of competition when it goes on sale on Friday morning. The iPad Air is noticeably lighter than its predecessors. If you are the least bit interested in the new tablet computer from Apple, you probably already know that. The company's engineers shaved just short of a third off the weight of the earlier version; the 9.7-inch Air weighs only a pound. What you may not know is this: Those 6.4 ounces make all the difference when, as you recline while reading or watching a movie, you conk out and the iPad falls forward to bonk you on the nose. The Air won't hurt you the way the old iPad did. The weight reduction and a 20 percent slimmer profile provide other benefits, too. My messenger bag strap didn't dig into my shoulder as deeply when my iPad was in it. My hand didn't cramp up while grasping the iPad Air for an hour while watching movies or playing games. But is Nose Bonking Reduction enough to justify buying a new iPad if you already own one of the 170 million iPads that have been sold over the last three and a half years? And if you have never bought a tablet computer, is this the one that persuades you to fling your laptop aside like crutches at a faith healing and embrace a new era? When the iPad Air goes on sale on Friday morning around the globe, it will face its toughest competition yet - from Samsung's Galaxy Note 10.1, Microsoft's Surface 2 and Amazon's Kindle Fire HDX. Google has a new Nexus tablet in the wings. The iPad Air will also compete against its little brother, the iPad Mini. Later in November, Apple will begin selling a new version of that tablet, which comes with a high-resolution 7.9-inch Retina screen and the same faster processor found in both the Air and the new line of iPhones. So how does the Air stack up? Compared with the Mini, the question really boils down to size. If all you want to do on a tablet is read books or watch movies, the smaller screen is excellent, and you can save $100 (the cheapest model of the Air costs $500. The new Mini costs $400). But I use the iPad for work, reading documents and occasionally even editing or writing on it. I also use it as a second screen (actually it's a fourth, but we won't get into that) on my desk for research on the web. The extra real estate provided by a larger screen matters at the office. If you decide you need the bigger screen, you will find a lot of benefit in the iPad Air. In addition to being light and slim, it loads apps and web pages quickly - faster than the old iPad, because Apple tailored software to mesh with the custom A7 processor and vice versa. It easily runs for 10 hours on a charge, just as Apple promises - despite the battery's smaller size and the increased demands put on it. In my test of pretty heavy use, it downloaded and played three hourlong episodes of "Game of Thrones" and a few hours of music. I scrolled through Twitter and Flipboard, played games and perused the web. That's almost a typical day for me and my iPad. It will get you through a normal day and then some with no worries. The iPad Air also sports two antennas to pull in Wi-Fi signals faster than the old one did. Called MIMO for multiple-input and multiple-output, these antennas make a noticeable difference when your fast Wi-Fi signal is weakest, like in a back bedroom or the basement. You'll have to have a recent MIMO compatible router to see the magic, though. But do you need to plunk down $500 or more for an Air if you already have an earlier version of the iPad? Notice I used the word "need." Even though I love shiny new objects, I really can't tell you to replace your old iPad; the improvements on the new one are incremental, not revolutionary. If you've never had a tablet, though, the answer is different. A tablet, especially this iPad, is a delight to use and will bring you more hours of enjoyment than any other electronic device I know of. Apple sells the devices in two colors - black and white. The company, though, calls them Space Gray and Silver because that's the color on the back of the tablet. It's a quirky company.) It also sells covers in six colors for $40 and cases, also in six colors, for $80. You can assume stores will soon be stuffed full of covers and cases of various materials and designs from many vendors to fit the new specs of this version. Damon Darlin, the international business editor, is a guest columnist for State of the Art.