I checked a similar service that also relies on the Vodafone network but they cover only 33 EU countries.
www.europasim.com
It costs 6 € per day, with 150 MB included (4 cent/mb), which is enough to work the whole day if I don't use video. Skype is fine. With the same card, I pay 2 € per day in Italy, with 500 MB included. Since it is prepaid, there are no fix costs and I recharge in advance and know how much I am going to spend. Important: I set the threshold to 140 MB a day, so I have a safety net, but usually I use 50-100 MB per day to work.