We currently use an index of bitcoin exchanges (including Coinbase, Bitfinex, Bitstamp among others). When comparing other services to ours, you should factor in all fees that may not be included in the exchange rate (purchasing fees, wire transfer fees and time).
We believe in simplicity and convenience. With LibertyX, there are no transfer fees and you can get your bitcoin as quickly as you can get to your neighborhood store. Additionally the rate shown is the rate you pay for your first $1,000 in bitcoin (thereafter a 1% fee).
The live rate is shown on every page (after you log in) and is finalized at the time the bitcoin is sent out (when you provide your bitcoin address).