Q - Does 3 include any wifi hotspots?
If you are in London like me then I guess O2 is still one to consider because of all the wifi access you get.
They don't usually. However, in my experience it's pretty rare to not get 3 3G coverage, even out in the sticks. I'm in semi-rural West Yorkshire and rarely get less than a 3G / 3.5G signal on my Nokia where people with Orange, O2 and Vodafone struggle.
If you are in London like me then I guess O2 is still one to consider because of all the wifi access you get.