I've ordered a T-Mobile sim (which is pretty daft living in NI) from Chitter Chatter which is £6 per month just to see how good they are. Orange and T-Mobile still haven't merged their 3G networks so I'm not expecting any 3G coverage, but it shows how bad this three situation has got. I sit at work and get little to no data (it kinda freaks me out!).
This time 6 months ago I had no worries.