On EE I’m currently getting unlimited texts/calls and 30GB of data (with roaming in EU and US) for £17.99/month (~$25/month). Makes US prices look crazy.
Three's coverage is garbage outside the big cities (and sometimes garbage in them!), and Feel At Home is never 4G.
Everything except Verizon is garbage in rural America.
They have a clause in the fine print, that says that you have to be in your home country at least once a month, in order to use this service. I thought it was great for me staying abroad for 6 months, but I could only use it for a little more than the first.