If you're looking to buy a new portable computing device, now or later, you'll likely consider old-school laptops along with newfangled tablets.

Tablet computers have taken the market by storm, and they're appropriate for many people. But for those who significantly engage in information creation as well as consumption, and for many business users also, laptop computers often remain the better choice.

Tablets do have their advantages. They're smaller, lighter, and typically less expensive than laptops. Their popularity is undeniable. Tablets are projected to surpass laptops in US sales for 2013--240 million tablets versus 207 million laptops--according to market research firm NPD Display Search (www.displaysearch.com).

Increasing tablet sales are contributing to the decline in PC sales. Overall sales of PCs--laptop as well as desktop computers--fell 4.9% in the fourth quarter of 2012 compared to 2011, according to market research firm Gartner (www.gartner.com).

The causes of this decline, according to Gartner, were a weak economy and strong tablet sales. "Tablets have dramatically changed the device landscape for PCs, not so much by 'cannibalizing' PC sales, but by causing PC users to shift consumption to tablets rather than replacing older PCs," says Mikako Kitagawa, principal analyst at Gartner.

Top-rated tablets include Apple iPad (www.apple.com/ipad), Samsung Galaxy Note (www.samsung.com/GalaxyNote), and Google Nexus (www.google.com/nexus).

So why would anyone choose a laptop today?

To gauge why, and to get a better feel for laptop trends, I reviewed a laptop from Acer (www.acer.com), the third largest PC maker in US sales, behind Hewlett-Packard (www.hp.com) and Lenovo (www.lenovo.com). Acer has a big presence in office supply, discount, and other retail stores.

I looked at an "ultrabook," which is a relatively new category of laptops that are thin and light, with plenty of portability, along with being a step up from tablets in functionality. Ultrabooks typically come in three sizes, based on approximate screen size: 11-inch, 13-inch, and 14- to 15-inch.

But if your plans for traveling with your laptop involve little more than occasionally moving it from office to conference room or from living room to kitchen, a better choice may be a "desktop replacement" laptop, which typically has a 17-inch screen that for many people is easier on the eyes.

The popularity of tablets has drastically diminished the popularity of the smallest of the laptops, the "netbooks."

In contrast to tablets, laptops have a separate keyboard, making it easier to type, and a larger screen, making it easier to see. Laptops are also typically more powerful and versatile than tablets, which makes them more attractive to businesses.

The Acer S7-391 Ultrabook I looked at has a 13.3-inch screen and weighs 2.87 pounds. This compares to 9.7 inches and 1.44 pounds for an iPad.

The unit comes with a dual-core processor, 4 gigabytes of memory, and a 256-gigabyte hard drive. Like many better laptops today, the hard drive is a next-generation "solid state" drive, which means that it works like a USB drive rather than a traditional hard drive. With no spinning disks, it's faster, quieter, and more resistant to bumps.

Another trend with laptops, also exemplified by this unit, is that it comes without a CD/DVD optical drive, making it lighter. As happened earlier with floppy drives, optical drives may be on their way out. They're becoming less relevant because of the increasing ease of accessing programs and content and backing up data using "the cloud," the Internet.

Like tablets and smartphones, this unit comes with a touchscreen, reducing touchpad or mouse use, which represents a third laptop trend.

Despite improvements in voice recognition, inputting still typically involves typing. With a tablet you type on its screen, or you can buy a stand-alone keyboard. In either case the ergonomics aren't as good as with a laptop. Because people tend to slump when using them, tablets can cause more neck and shoulder problems than laptop or desktop computers, according to a Harvard School of Public Health study (www.hsph.harvard.edu).

Conversely, desktop PCs are more ergonomic than laptops, further exemplifying the tradeoff between portability and ergonomics. Similarly there's a tradeoff economically. iPads 4s start at $500 and go up to $830, for instance, while Acer ultrabooks start at $550 and go up to $1,650. Average ultrabook prices are projected to drop to $500 in 2016 as their technology matures, according to market research firm GBI Research (www.gbiresearch.com).

Even with the encroachment by tablets, manufacturers will likely continue selling lots of laptops. For many people, the added power, efficiency, and comfort justify the cost.