Is this only a UK to US thing or can I open a CitiBank account here in the US and then add on the UK account later?
It says 'You must be resident in the UK to open a Citibank Current or Deposit Account' so once you're here you will be able to open the accounts.
If you have a Citibank US account, it's even better as you're then able to transfer money from your UK$ account to your citibank US account. It's the only 'external' account you can do that with. The UK$ account is quite limited in that you get a debit card to use, but if you're looking to transfer money to a US savings account for instance, you will have to send a check to the bank's postal deposit service.
The Citibank US checking accounts charge monthly fees so I have stayed away. I'll be posting checks to my Ally account to then fund my US investments when the time comes.
My husband opened the same account with CitiBank. He waits until the exchange rate is really good and then transfers £'s to the dollar account.
That's right, the 'citibank exchange rate' is fixed for a period of time, I assume they buy dollars at a certain rate. I looked the other day, and the rate was better than the market rate that XE was quoting. I just looked now, and converting £100 will now get you £3 more with XE's rates, so it's all about timing. Of course the Citibank option is fee-free, so it's all about the rate.