At work only vodafone have a decent network for data. We can get decent voice signal across most networks but only voda have reliable data throughput, probably due to the 4 masts on our building as all corporate mobiles/ blackberries/ipads etc.are all on voda
I'm on O2 currently, I was a little pee'd of as I'd asked the lads on the team before signing up and they still said they had 4 bars, as iphoneistas I assumed they knew what data was....... I've rung O2 and they refuse to look into the mast as its not reporting any errors.. Grrrrr