Most Networks now offer resonable Mobile Broadband, within good coverage they work well, in poor signal areas there shite, Ive pretty much used all the UK Networks and in good coverage will give between 3.5 to 7.2 Mb speeds. The trick is to find the best Network coverage where your going to use it most of the time.
Almost all new doggles will have 4 modes, 2.5G (GPRS about 60Kbs), Extended 2.5G (EDGE 128Kbs or 236Kbs, but not used in the UK), 3G, 330Kbs, and 3.5G (HSDPA or variants of, which can be up to 7.2Mbs).
Within the Software you should be able to change Network preferences, ie, 'Prefer 3G but allow GPRS' so change that to 3G+ only, this wont do you any favors in poor 3g signal areas but it will stop the dongle falling back on 2.5G and staying there untill it decides to revert back to 3G again. The dongle reverts to GPRS in poor 3G+ signal areas as 2.5G generally gives better coverage due to it being part of the GSM (2G) Carrier component.
GPRS (2.5G) is pretty much useless, 3G on a dongle is quiet good for normal surfing, a lot faster than on your phone, where as 3.5G (Broadband) shows its true colours when downloading large files or watching videos etc.
If using the doggle full time then go on contract, or if the usage is on a Add Hoc basis I wouldn't bother with a monthly contract, grab yourself a Sim Free Broadband doggle of fleeBay and go with a normal PAYG Voice Sim, theres some nice tricks you can do with T mobile, Orange, Vodafone and 3 Mobile Sims which will give 3G or Broadband usage for about 50p a day or less!
Chris.
