Optus provides "up to" 8GB of data with a relatively generous six-month expiry, although there's a sting in the tail of that offer, which we'll cover shortly.
The Mini WiFi comes with security enabled out of the box via a password that's permanently printed on the back, inside the cover. Once you've set up the account (our review unit came with a pre-configured account), you could just fire it up and surf securely. The in-built web-based configuration utility isn't particularly hard to deal with if you want to tinker or set your own unique SSID and password.
The Mini WiFi is powered via a 1400mAh Lithium-ion battery. In our tests, we managed to keep the unit running and providing data to an iPad and a pair of mobile phones for four hours and 10 minutes, which is pretty impressive for a portable router. It's not quite a full day's work if you use it all at once, but if you're moving between other data sources, it could supplement them nicely. Likewise, Wi-Fi range was decent for such a small unit, and we found we could easily move between two rooms and maintain a decent connection.
Mobile broadband is, by definition, quite variable depending on location and service usage. In our tests in Sydney and Adelaide, we managed variable speeds from 1.67Mbps up to a maximum of 3.40Mbps using the Speedtest.net utility on an iPad connected to the Mini WiFi Modem.
There's only a single factor in the Mini WiFi's hardware that we're not that fond of, and that's the display screen. While it makes a nifty backup mirror, that same reflective surface and low brightness OLED screen is almost impossible to read in direct sunlight. If you need to check the status of the connection during daylight hours, it's a case of squinting, holding your hand over it to block the sun or just plain giving up.
The other major catch with the Optus Mini WiFi has nothing to do with the hardware at all, but more to do with Optus' current data provisioning rates. The Mini WiFi works on a prepaid basis, and at the time of writing, Optus' standard for data charging, irrespective of the recharge value on the modem is to charge in 10MB blocks. The first 30MB per day is only charged as 10MB, but still, if you used the device only intermittently, you'd burn through a lot more data than you might expect, even if your connection and actual data usage was quite low. What's truly odd here is that while Optus is charging data at 10 times the rate that Telstra or Vodafone do, if you use Virgin Mobile's broadband, it's charged at a per kilobit rate, a full one hundred times less than Optus does. The weird thing there is that Virgin Mobile's a fully owned subsidiary of Optus. There has to be a happy medium somewhere in there, but we're certainly not happy with the concept of being slugged 10MB per data per session.