I'll be getting it on the £21.50 a month contract. It amazes me. It's such a good phone and it's free. The total cost at the end of the contract for me will be £516. For an iPhone 4S 64GB on a £21.50 a month contract the phone itself costs more than the total Xperia S cost (£520) and then there's the total contract of £516 to add on. That's £1036 for a phone!
I don't usually let cost dictate the phone I get, but at more than double the cost for an inferior spec phone, it's an easy choice.
Can't wait for it. Were you given a release date or is it still early March?