Although I like to use BlueBird from American Express for my teenager's use, American Express take 3-4 business days to show available funds. This is after the money gets taken out of my bank account. Add another 2 days until they take the money out, and you have a 5 to 6 business day turnaround time for your money to become available.
American Express are definitely shrewd operators. I don't mind making a little off of my float but 4 business days is ridulous!
I saw a person's comment to someone who complained. They said, "what do you expect, it's free." Give me a break. So you should expect crappy service because they don't charge service fees? They make up for it plenty on the float.