We have both also, and if you do go into another country O2 is better as it's only £2 as opposed to threes £5, and with O2 you can tetherIt might not be quite as good as advertised but it's still pretty good. H has 3, I have O2, it would cost me £2 each day for a similar service. It's a saving of several bottles of wine when were in France.
So far we've had no real problems with poor connections.