yes you can pick up very good deals in the states but at the moment you can pick up very good deals here to, plus fact of that is the warrenty. you can also check your prices on line before you go, then look in the duty free shop, yes it is still duty free if you go to the states, so again good savings and you get your warrenty to. it pays to shop around good hunting
Depending upon which state you are visiting (be aware of local sales tax rates) your best approach might be to get a mail order delivery to your hotel. Quite a few US sellers will do this, such as B+H apparently. click here and scroll down to the posts by Sean LA and Elan Remford. Even if you just pop into a store and get a good price, it will still beat the pants off anything that you'll pay in the UK right now.
I asked my son to call in at B&H in New York just prior to Christmas and check on the Canon 5D This would have cost £1100, but with no UK warranty. To buy in this country £1314 inc cashback from Canon.
Told him not to bother, £200 difference and no warranty, IMO just not worth it.