Yes. I use one a back up when visit clients.
Performance is generally good but depends on location. I have had up to 5 computers running on one via a router, albeit in an area where the nearest mobile tower was only 1km away over flat ground.
See:.
http://barlaventositblog.blogspot.com/2008/08/prepaid-mobile-broadband-portugal.html
And
http://barlaventostravelblog.blogspot.com/search?q=vodafone
Coverage in Mountains is patchy. The system depends in line of site and to get good performance you need a good 3G mobile phone signal. I strongly recommend potential buyers to test their signal first with a good 3G phone or computer equipped with a dongle before purchasing.
There are three basic units on sale in Portugal, Vodafone, TMN and Kanguru. They can usually be had in any Mobile phone shop, Worten, Vobis and Fnac Stores.
Prices vary but if you are in the Mountains you will probably want a powerful dongle like the Huawei E172 which runs at up to 7.2 Mbps and currently costs € 49.90. in Worten
