By HOMER ASHBURN

GIVEN a choice between a portable device that has a million and one bells and whistles, which also allows you to make telephone calls, and a portable device that does just one thing, most people would choose the smartphone with the killer GPS app over a dedicated portable sat-nav that only gives you directions.

And the indications are that the rest of the world feels the same way.

After all, when Google and Nokia recently gave away professional GPS software for selected smartphones, according to various reports, the share price of GPS maker TomTom fell 9% on the Amsterdam stock exchange.

And it gets worse.

According to a New York Times report, apparently 40% of all smartphones owners and 80% of iPhone users use their mobile devices to get turn-by-turn directions, exactly the thing that standalone sat-navs do.

Garmin nuvi 765 GPS navigator.

You see, in the old days, portable GPS had the upper hand.

They had the assisted turn-by-turn directions, the strong visual displays and the sexy voice instructions.

Mobile phone users, by comparison, only had Google Map's text-driven instructions.

Nowadays, with the new apps on smartphones, wireless broadband and 3G networks, the idea of using your iPhone to find out where you want to go, Garmin-style, is certainly an attractive one.

As an acquaintance once said: "Who needs a Garmin when I have my handphone? It costs the same but my phone lets me make calls, type SMSes, surf the Net, check my emails and get directions to any where I want to go."

Also, especially in more developed markets, GPS smartphones provide faster re-routing directions, updated traffic information and even regular updated GPS information, something that you have to do on your own initiative with a portable sat-nav.

Strong arguments indeed on why smartphone GPS are the way to go.