Smartphones are big for small business. In fact, many mobile workers now depend on these all-in-one digital Swiss Army Knives that offer support for third-party applications, messaging, Web browsing, GPS navigation, media playback, and photo and video capture.

Oh, and they make calls, too.

But there are a growing number of different platforms on the market -- including BlackBerry, iPhone, Android, Windows Mobile, Palm Pre and others -- therefore deciding which one is best for your small or mid-sized business could be an overwhelming endeavor. So we turned to a couple of tech experts to discuss what a mobile worker should look for in a smartphone platform.

The basics

Smartphones are an increasingly popular choice for business use, but regardless which of which operating system you go with, the handset must meet a few key minimum requirements, says Scott Steinberg, publisher of Digital Trends.

"Battery life and wireless coverage are two big ones," says Steinberg, who is based in Atlanta. "Because of all of its features and integrated wireless radios, smartphones can consume a lot of power, and the last thing you need is to be on the road or at a trade show and there's only one bar left."

As for coverage areas, which can greatly affect call quality and data speeds, Steinberg suggests to do your research by visiting the websites for carriers -- such as Verizon, T-Mobile, AT&T and Sprint -- and click on the map that shows coverage areas. "Many people assume the smartphone will work the same everywhere in the U.S., and elsewhere, but this is simply not the case," he explains. "It's also not a bad idea to talk to colleagues or friends on that network to hear first-hand about coverage, as the last thing you need is to be on the road and you can't access your e-mail from client about a cancelled appointment."

Ted Schadler, vice president and principal analyst at Forrester Research, a Cambridge, Mass.-based technology research firm, says before deciding which smartphone to invest in, figure out what applications your business requires and if they're supported by the platform. "The horizontal app is e-mail, of course, but after that you'll need to list any other apps you'll want to run," says Schadler. A small or mid-sized business "will also work out the cost per device, how many you need for your staff, the cost of the data plan, and any device management software or mobile middleware you might need."

Consider being device agnostic

Schadler, who has just published a report entitled Technology Populism Fuels Mobile Collaboration: When IT Supports Personal Mobile Phones, Mobile Collaboration Ensues, says the trend is moving towards a "bring your own smartphone" practice. In a survey completed by more than 2,300 IT decision-makers in the U.S. and Europe, one in four are now supporting an employee's personal mobile device -- so long as the applications are platform-agnostic and meets the company's security protocols. The gotta-have-it iPhone from Apple is the "big disruptor" for this paradigm shift, says Schadler.

Deciding which smartphone platform to go, however, might be dependent on the industry you're in, adds Schadler. If you're in regulated industry -- such as health care, pharmaceutical, insurance, or financial services -- you might have strict privacy requirements, such as protecting customer data, remote wiping of device if the smartphone is lost or stolen, and so on. "There are many, many different kinds of policies in these industries so you have to be careful about which phones you're supporting to ensure they meet regulatory compliance," says Schadler.

"If you want managed devices, you really only have one choice, which is BlackBerry," adds Schadler, "as RIM supports more than 450 policies -- but it'll cost you a license fee per month, per user." He adds, "Otherwise, Windows Mobile and iPhone are basically free if you're running Exchange."

Steinberg agrees with Schadler on the additional requirements for any smartphone consideration. Your priorities should be "security and privacy issues must be addressed, support for enterprise-level e-mail, and whether or not you easily sync your data with a PC," he says. "And depending on what you need, access to the company's Twitter or Facebook account while on the road might be important or GPS to find your way to a meeting or wireless or on-demand software purchases at an app store."

Pros and cons

The following are a few thoughts on each of the major smartphone operating systems:

• BlackBerry

Pros: Reliable, fast and secure "push" e-mail; physical keyboard in most models; good battery life; supports multiple accounts.

Cons: Browser not the greatest; App World doesn't offer great selection or intuitive interface.

• Windows Mobile

Pros: Supported by the broadest range of devices; Outlook and other Windows programs sync smoothly with a PC.

Cons: Interface and stability issues; fewer apps than most other smartphones.

• iPhone

Pros: Elegant and intuitive touch interface; more than 65,000 apps in App Store (many of which are free); great consumer device.

Cons: No physical keyboard is obstacle for many; battery life trails other smartphones; still no MMS support in U.S.

• Android

Pros: Powerful and versatile open-source operating system; seamless presentation and access of online Google apps; good user-interface.

Cons: Not a lot of supported devices or software; Android Market not as intuitive as Apple App Store.

• Palm webOS

Pros: Open-source operating system anyone can develop for; can support multiple apps open at once; offers both physical keyboard and touchscreen.

Cons: Unproven for business because newest OS; poor selection of software and only one device (Palm Pre).