Their 3g service quite good, the Iphone sits on it so you can imagine they have beefed it up to handle most overloads. Although if you are in a rural part then I really dont know how it would fair but most big towns and cities are taken care of.

Yes they do, its 250 MB on normal and 500 MB for business, still check up what is what on ur plan.

Tetherin on iphone, I dont know but they cried devil when i mentioned it on my diamond, so I dont think you could get away with that.

They have a range of wifi hot spots but again limited to the larger cities, I am from cardiff a capital city for that matter but still wifi is a very limited, if you are in London or Birmingham on the other hand then lucky you...