Funny you should mention getting a signal on Vodafone. When I was with them, the network used to go down with alarming regularity - especially for texts, which is a big problem in my opinion. You could pretty much guarantee the texting would be down at least once a month.

Switched to Orange, and I am no fan of them, but it's never been down once - despite what people used to say, that Orange used to hold on to texts to delay them on purpose - no idea if this is true or just an urban legend.