I just signed up for Amazon Prime and honestly I'd love to keep paying for the service, but I would rather cancel after a year because of poor service - not on Amazon's part, but on their chosen carrier - UPS. I never ever get anything I order on time, even though I have someone waiting for the package each time I know that a package is arriving.
I signed up for their "My Choice" but it doesn't even help at all because they don't even come knocking on the door.
I'd think twice about online shopping and just go for the brick & mortar at this rate. You'll never get your packages on time.