This review is for this device not the carrier, it is a description of how the device works here in The States and should work throughout the UK.
First look
Installation
Connection
Advantage
Disadvantage
Conclusion
I've been using the Sprint MiFi since Thanksgiving and I'm happy to report that the MiFi has done exactly what the company said it would do.
The Sprint MiFi is a silver, credit card-size portable router. So, if you have one of those router connected to the phone line and the computer... this is the same thing except it is free of any cables. I bought the MiFi based on the early pre-release reviews and because I wanted to upgrade from the access card the Novatel U720 which took up one of my valuable USB ports. The immediate effect is that I have now a "high speed" internet access for my laptop and a wifi speed for my T-Mobile (Edge-enabled) Blackberry Curve. Not to be confused, The MiFi-- this portable router-- is not as fast as your cable-internet connection at home. It is primarily designed to give you a certain amount of freedom where you can't get an internet connection or to be used in your travels.
Installation.
The MiFi package comes with a small instruction booklet but I found actually connecting my Apple laptop via the Airport card very difficult. I called Sprint and it took us the better part of 30-40 minutes until the MiFi gave us the signal. That has been the only drawback to this.
Connection.
The MiFi gives you a 3G (and promises to give you 4G when it is rolled out in your city) here in Miami (FL) and here in South Miami, Sprint's service has always been mediocre, even with the Novatel U720. If the signal is weak, then no device will give you a better performance. However, the MiFi did give me advantages that made me want to upgrade.
The MiFi card also becomes extremely hot. I normally have a small fan blowing cool air into the vent of my laptop, I just draped the MiFi over the fan and the card remains cool.
Advantages.
Portable. The MiFi is no bigger than 3 credit cards stacked. It fits comfortably in a shirt pocket and is completely detached.
You can connect up to 5 devices from it. I have connected 2 devices and there's no discernible slowing down of service.
The card can be programmed to have a secured connection. So, if you're out and about, you can create a WiFi connection for only the people you allow a connection for.
The card is now $50 with a 2-year agreement from Sprint (I paid $150 w/ $50 mail-in-rebate.)
Disadvantages.
The card can become extremely hot to the touch, if not with a fan or some kind of ventilation near.
Installation will require a quick call to Sprint as the supplied information was not enough.
The device is good for about three (3) not four hours of battery life.
Conclusion.
The MiFi has nothing to do with the download limit set by the company (i.e. Sprint) this device only access what is available and it does just what it promises. This portable router can literally give several people internet access just by being near this object. This is a handy device to own.