If you ship with USPS it is at your own risk. We have been having lots of trouble with USPS in not scanning products and thus tracking is hit or miss at best. Furthermore we have had several packages that show out for delivery and have not been delivered for over a month, if at all. We will not resend or cancel an order until USPS approves doing so and that could take a month or more. There is virtually no customer service from them either. You put in a call to file a complaint and "they will get back with you in 2-3 days" and sometimes its a week or more if they even do get back with you. So getting any resolution from them is questionable.
Needless to say we are not happy with the lack of service from USPS but if you'd rather save a few bucks and play Russian Roulette with your package that is up to you.