Hi.
Huawei E220 supports Windows XP out of the box, but requires firmware and software updates in order to use it with Vista, which are detailed and simple to do, as detailed here - http://www.mobileconnected.co.uk/usb-modem-huawei-e220-on-vista-take-2/
The Globesurfer Icon 7.2 and 7.2s support Vista directly according to our contact at Option, their manufacturer.
The E220 and Icon 7.2s use the European 2100Mhz 3G frequency, whereas the slightly more expensive Icon 7.2 will work in the United States as well.
The E220 is nominally rated at 3.6Mbps, the two Icon units obviously 7.2Mbps as their name indicates.
In the UK, only 15 airports and the very centre of London have 7.2Mbs enabled base-stations (Dec 2007), on Vodafone, the other Networks have not announced them at all that I have heard of. In addition, a recent and eye-opening review of mobile internet provision by The Register found that data speeds were normally not able to exceed the 1.8Mbps speed that forms the bottom rung of the 3G speed ladder.
http://www.reghardware.co.uk/2008/01/16/review_vodafone_usb_modem/
Therefore, unless you are in a very large and modern capital city, there will be no functional difference for most people between 1.8, 3.6 and 7.2Mps devices. This will change over time, certainly in five years time the map will be different, but at present unless you reside in a major city, the important thing is to be covered by 3G at all, rather than worrying over which speed it is.
Typical download speed in London were in the 620k/sec (0.6Mbps) and in the outer regions of the city, 110k/sec maximum (0.1Mbps).
Before this stops you completely, remember that when broadband first started, all websites and email worked perfectly on a 512k (average 50k/sec)connection and everyone applauded when 1Mbps and 2Mbps were reached. Not many people with 8Mb broadband at home get 8Mbps speed. Only P2P and Bittorrent style massive file downloading is unsuitable for USB SIM based modems, all general work and browsing is fine.
Reliability wise, I have asked our Returns department and they say neither device has any issues with above average fault or error rates.
Bear in mind that most tariffs, certainly in the UK and USA, are heavily capped. Often the limit is 1Gb or 3Gb per month depending on which tariff you have bought. This is sometimes for total traffic, not just traffic down, so read the small print if you intend to use file sharing or heavy downloading. Going over the limit can result in high charges per Mb (not Gb!!) downloaded, so make sure you get it right or install a traffic Mb counter program.
If you intend to go against the norm and use your mobile phone's SIM instead of getting a dedicated one just for the Huawei/Icon, please check your data tariff again. Often, mobile *phone* tariffs for data use cover data used by browing the internet on the *phone* and do NOT cover use of the phone connected to a laptop for internet use. To reiterate and clarify - using your mobile phone's SIM in the device might not be covered by your data plan and big bills could result. It is far better to get a proper data SIM from your preferred Network designed and enabled for laptop data use.
Finally, you said you were in Spain. Most data tariffs from Networks do not let you use the "free" 1Gb or 3Gb allowance when abroad. Therefore you will probably be looking to get your SIM card from a Spanish, not a UK Network.
Sorry for the long post, but I hope I answered your query comprehensively and help you to get the best deal.
Regards
Ivan