The other consideration is that within the EU there are caps on the rates that EU mobile phone/SIM providers can charge and nowadays I use my UK SIM within the EU without bothering to "go local" any longer. I currently am on giffgaff in the UK, and if you wanted me to send a giffgaff SIM to you so you can activate it before you leave I am happy to do so. There is a "
Refer a Friend" scheme and the net is we both end up getting £5 credit. Other than that I would go for Three because of their "
Feel at Home" product.