As modern smartphones begin to look more alike, there is one user preference difference that has kept phone design firmly in two camps: the keyboard -- virtual or physical.

All smartphones offer a virtual keyboard that pops up on screen for texting, e-mailing, entering Web searches and the like, but that doesn't satisfy all users, many of whom feel much more comfortable -- and believe they're faster and more efficient -- with a physical keyboard.

That's why most smartphone makers still give users a choice.

It is not a manufacturing decision to be made lightly since there is a considerable financial penalty in providing a full physical keyboard.

A virtual keyboard on screen is just a few more lines of software code; a sliding keyboard brings significant design and manufacturing costs.

That the demand for a physical keyboard remains strong may boil down to a generational issue. Young smartphone users, who've grown up in a touch-screen world, seem perfectly happy with on-screen keyboards offering no tactile feedback other than perhaps a beep or buzz. In fact, to watch a typical teenager texting furiously with thumbs or fingers dancing across the screen is to marvel at the dexterity involved.

Many older phone users, who may have actually used a typewriter or at least a desktop computer with a full-size typewriter-style keyboard, feel less comfortable with the tiny keys crowded on screen in the typical virtual version.

Phones with physical keyboards have been around for a while, although many of the first ones, like BlackBerry or Palm units, had tiny keyboards sharing space with screens on the front of the phones.

Many men, with larger hands, often complain about the difficulty of hitting the right key or hitting more than one with the resulting gobbledy-gook requiring constant backspacing -- if they can even find the backspace key.

Will one or the other eventually win out? The smart money would probably go with on-screen keyboards, for reasons of economy for manufacturers if nothing else.

Also, as screens get larger -- with some phone models approaching 5-inch screens -- on-screen keys get bigger. Android phones now come with Swype technology that allows the user to just drag a finger across the keyboard and the phone figures out what word is being spelled -- offering choices in case best guess wasn't good enough.

In the meantime, however, every major cellphone manufacturer has opted to continue to give consumers the choice, with all featuring one or more "sliders."

The major exception is, of course, Apple.

And even here the aftermarket has stepped in. Users can purchase a case that affixes to the back of the Apple phone and slides out to reveal -- yes -- a full physical QWERTY keyboard.

Even the most current model lines of phones offer the option.

Motorola offers three of its new flagship DROID phones -- the DROID Razr, the DROID Razr Maxx and the DROID 4 -- that from a distance of 3 feet can't be told one from another.

The difference? Pick up a DROID 4. Hmm, a little thicker. Why is that? Because it slides open to reveal its "PC-like, edge-lit QWERTY keyboard," Motorola is happy to tell prospective buyers.

Fans of touch-typing can rejoice, at least for now. The keyboard with buttons you can actually feel and push is still with us.