I have used Truphone local anywhere since early this year, I love it. Absolutely no problems whatsoever, and their rates are awesome (here in Canada). In fact for the use I make of cell phones (on a strict necessity basis) it turns out cheaper than any local company here. It always works... and I even use it for the occasional data roaming (email and chat). I started with $40 this year, now I'm down to $14 or so.
I can't recommend the sim enough, though it is true, their website stinks and they promised to changed their wrong rates in April already when I contacted them