As it happens I am using a Vodafone (their spelling) dongle at the moment.
It works well - even in some places where usual mobile phone coverage is patchy. I got it because I am away from home a lot and have found that the 3Gigs for £15 just gets me through the 30 days you get before evaporation. You can also stack up credit so that it comes into play as your last 3G runs out. The only niggle is that it keeps on wanting to reload the software claiming to not recognise the device. I am sure there are as cheap or cheaper deals going but it works for me.
VnV