Ok, so what about the all important speed? Vodafone's 3G network promises a maximum down-speed connection of 384 kilobits per second (Kbps), or 48 kilobytes of data per second (KB/s). In testing, we regularly achieved speeds of around 264Kbps (33KB/s, or around 2MB a minute), with top speeds of 360Kbps (45KB/s).
On paper, Wi-Fi can leave 3G in the dust. An 802.11b (the slowest Wi-Fi protocol and the one most commonly used by Wi-Fi operators today) network offers a theoretical maximum speed of 11 Megabits per second (Mbps), although only about 5 Mbps is actually possible. In practice, however, the top speed at a hotspot depends on the speed of the backhaul broadband connection, which could be anything from 512Kbps to 2Mbps.
None of these figures tell the whole story, though. Both 3G and Wi-Fi are contended services, so everyone within a hotspot or a cell has to share the available bandwidth, says Niall Murphy, chief technical officer for Wi-Fi operator The Cloud.
"If there are ten people in one 3G cell, all trying to download a 5MB MP3 file, then they'll see their maximum speed drop to something like 60 kilobits per second," he explains
The same theory applies to a Wi-Fi hotspot but in practice, when ZDNet UK tested a series of commercial Wi-Fi sites around London, we encountered very few other users and usually enjoyed the maximum bandwidth.
The speed issue isn't black and white but what is clear is that Vodafone do give the option of dropping down to GPRS if 3G isn't available, so employees who are entrusted with a Mobile Connect card can always connect in some shape or form anywhere in the UK. Wi-Fi users meanwhile may find the local Starbucks has lost its connectivity, and that the staff don't know how to get it back
The price is right?
Rock and hard place best describes the pricing alternatives at the moment for IT professionals weighing up the options for both technologies. Wi-Fi pricing has been too high, say analysts, pointing to £6 (AU$15) for an hour's access, or £85 (AU$218) per month for unlimited access to BT Openzone, for example.
The Cloud's Murphy, whose company resells access to its network to other operators, such as Openzone, believes Wi-Fi pricing needs to be reformed and that 3G could be the catalyst. He thinks 3G will put pressure on operators to move to a post-pay environment, in which customers are charged for actual usage, rather than today's pre-pay model, where payment is made up front for a fixed period of access that is often more than required.
"When people have to pay for access time that they may not use, there's a perception that they don't get value. Frankly, I'm amazed that people put up with it. It must be an early-adopter issue," says Murphy.
Vodafone is expected to launch a Wi-Fi component to its 3G service later this year. Stonadge says this will help Vodafone to offer a "complete suite of core solutions" to its customers. It's not yet clear how this will be priced, but customers will probably be charged using the same pre-pay system that Murphy says needs reform.
Per-minute Wi-Fi charging could be introduced if the market demanded it, says Stonadge. "We've yet to fix the pricing. It's more likely that we'll charge by the session, which could be 30 minutes or an hour, because that's what is in existence today."
Vodafone's 3G pricing, based on the amount of data that the user sends and receives, has also caused some concern. The top tariff for power users offers 500MB of traffic for £85 plus VAT per month, which works out at more than a grand per year per user. "The feeling we've had is that the ability to have true mobile broadband provides enormous value," says Stonadge.
But the UK pricing isn't the whole story. The massive cost of roaming onto one of Vodafone's 3G networks in continental Europe could deter a lot of potential users, says analyst Bubley.
"The initial tariff for Vodafone 3G isn't priced for the mass-market international traveller," he says, adding that it can cost up to £5 to download a megabyte of data when roaming. "For a 5MB Powerpoint presentation, that can be an expensive exercise."
Also charging users for the amount of data they download isn't sustainable, adds Bubley. "There is a market for cellular data if it's priced correctly, which means flat rate. I'm very sceptical that pricing per megabyte will be successful."
Vodafone offers several tariffs, starting with £10 per month for 5MB of data. Users who exceed their tariff limit will be charged extra, so companies won't be able to predict exactly how much they are going to be charged. Our testing showed that users could be unpleasantly surprised by how much data they transmit while surfing, running instant-messenger programs or connecting to a virtual private network link.
The choice is yours
So, 3G or Wi-Fi? Or both? Murphy and Stonadge argue that the technologies are complementary, even though both give high-speed connectivity, and that users will soon be able to buy packages that include 3G and Wi-Fi.
"The key is one-bill roaming, covering both Wi-Fi and 3G," says Murphy, who claims such a service could be available in the UK later this year.
Although Vodafone plans to launch a card that integrates both 3G and Wi-Fi within months according to Stonadge, Bubley is sceptical of users enjoying the "seamless" merging of 3G and Wi-Fi any time soon. "Seamless connectivity is very important, and virtually impossible to get right. The idea of having faultless handoff from one tech to another without user awareness is very unlikely," he says.
Given this warning, some companies may prefer to hold off from either Wi-Fi or 3G until both technologies are bundled together, especially those firms whose employees don't have to access corporate systems. "For someone who wants plain vanilla web access, such as email and downloading pdf files from the Web, it's much easier to just go to an Internet cafŽ," says Bubley.
Those chasing a competitive advantage, or keen to get their remote access sorted, face a trickier decision. 3G is particularly suitable for people who spend large amounts of time working in other people's offices, says Stonadge.
"There are a number of cases where the broader wireless coverage of 3G is better than Wi-Fi. The classic case is that of a consultant who spends a lot of their day at customer sites, which typically don't have Wi-Fi," said Stonadge.
But IT managers must consider the issue on a case-by-case basis, warns Bubley. "If you need ubiquitous access to your servers and are on the move a lot, the cellular side is attractive. But, if there are a couple of locations you go to regularly, it could be that Wi-Fi is best," he says. "You need to look at the question on a case-by-case basis, looking at the applications and devices that will be used, and traffic and usage patterns."
ZDNet UK's Graeme Wearden reported from London.