First and foremost, the thing that defines a mechanical keyboard is the key switch it uses. Most budget keyboards today use dome-switch technology, which registers a keypress when you type and push down a silicone dome and connect two circuit-board traces. (This technology is also sometimes referred to as "membrane switch" or "rubber dome," with minor variations in the essential design.) Though this style is easy and inexpensive to manufacture, pressing the keys requires a relatively large amount of force, which can result in a heavy, mushy feel to the fingers and a lack of either tactile or auditory feedback when you type. Plus, after a fairly "short" time (five million keystrokes, give or take), the domes can lose their springiness or stop working altogether. So, you'll probably have to replace the keyboard at least once or twice over the life of the computer that you use it with.

Mechanical switches, by contrast, get rid of the silicone altogether. Pressing down on the key activates a real, physical switch, usually involving a spring as the pushback mechanism, that registers what you type. Because the parts used are much more substantial than those in dome-switch keyboards, mechanical keyboards typically have a much longer life span. (Many boast ratings of 50 million keystrokes or more per switch, and may well outlast the first—or fifth!—computer you use them with.) The typing feedback also creates a more direct relationship between your fingers and what appears on the screen. Because of the hardware involved, mechanical keyboards tend to be thicker, heavier, and more expensive than their dome-switch counterparts. They are more of an investment, but one that will pay off in sheer satisfaction if the quality of typing really matters to you.

When shopping for a mechanical keyboard, you will want to pay attention, above all else, to the kind of switch it uses, and whether it offers auditory feedback (in other words, a click you can hear) or tactile feedback (a "bump" you can feel), or both. Also important is the amount of pressure that the switches require to activate (the "actuation force"). That will greatly affect its functionality and the possibility of finger fatigue.

In any case, whatever you want from a keyboard, you can find a mechanical keyboard capable of making it a reality, with more heft, longevity, and style than you may have thought possible. Mechanical keyboards are back and here to stay, with more variety than ever for laser-focused typists, hard-core gamers, and everyone in between.

If you're not wedded to mechanical key switches, check out our overall roundup of the best general-purpose keyboards we've tested, as well as the best gaming keyboards. And if you're in the market for a pointing device to go with your keyboard, see our lists of the best computer mice and the best gaming mice.

Their switches aside, mechanical keyboards have the same feature considerations as other kinds of keyboards. You may want key backlighting, whether of one color or an entire spectrum, that you can program at your whim. ("Per-key" RGB backlighting, in which you can program each key across the whole RGB spectrum, is the ne plus ultra of key backlighting, but it adds to the cost. See our favorite RGB keyboards.) Multimedia controls, whether they're activated by pushing separate buttons or using a Function key to access a secondary ability on one of the standard keys, can make it easy to adjust volume or move backward and forward in your track list while playing music.

Look for convenience features such as a volume dial or roller. (Corsair is well known for nifty volume rollers on some of its high-end mechanical boards, but other makers have adopted them, too.) And dedicated macro buttons can be a real boon for gamers, saving you the trouble of executing tricky key combinations or menu manipulations every time you want to perform a common action.

Most mainstream and gaming models offer a 10-key numeric pad, which laptops frequently lack, and is a necessity for anyone who needs to tally numbers or enter data into a spreadsheet. So-called "tenkeyless" models slice off the numeric pad in the interest of space savings and keeping your typing and mousing hands closer together. Bear that in mind if you're looking at gaming keyboards, as tenkeyless models are a recent trend, especially in that subclass. If you want to go even smaller, so-called "60%" keyboards eliminate even more keys. Check out our 60% keyboard guide for everything you need to know about the category.

Mechanical keyboards can be particularly well-suited for use with Macs. Many come with Mac-compatible configuration software, and you can even pop the keys off some models and replace them with Mac-specific keys such as Command and Option. Our roundup of the best keyboards for Macs gets into those details.