hi zarina. i have a myus account, which gives me an address in florida. they give you an option of what value to declare on the customs form -- either wholesale or retail. if you choose wholesale, they usually declare around 30% of the retail price of the item. i had this option going for a while and it saved me heaps of customs fees but recently, they used a courier company to send me some items and they have since told me that this option is no longer available for australian customers. i recommend checking with them first to see if you can get stuff sent to you at wholesale value.
also, you have to keep in mind that you would have to pay usa sales tax for some retailers sending items to florida. for example, neiman marcus has stores in florida so you would have to pay the tax. that's why i still purchase via online chat with neimans because there's no tax.
the service itself is very efficient and i have not had a problem with them. the annual fee can be pretty high but i have saved heaps on the shopping so it all balances out.