If your phone goes faulty with three your in trouble, their service guys can't fix anything. (2 new nokia phones all faulty, refused replacement only repairs and only had both 1 hour)
Three support and services is all in India, a simple question or problem can have you on the phone for hours, going round in circles and constantly being hung up!
Their coverage in ireland is pretty crap, their maps to show coverage are just plain blatant lies, my phone had to be setup to use O2, Orange and Vodaphone networks which is not covered by my free minutes on most occasions.
A text message can take hours, sometimes days to arrive from three...
3g for video calling is only available inside major cities.
But i have to give it to them, my first 4 months on three were hell, but they sorted it all out and now i have no problems, but my phone is very seldom on the three network.
A friend signed up recently, new nokia phone arrived faulty, three weeks later they still hadn't replaced it, he tried to cancel contract only to be told no, you have gone over your 7 day grace and he hasn't even been able to use their service, three want 500 quid to cancel..
Just be very wary mate, they use all the tricks in the old book and don't want to know you when there are problems.
I eventually got an indian freind to ring em up and give em hell in their own lingo.