I am sorry to say, but it not user friendly at all.
Keeping track of so many addresses can be a real pain especially if I am a successful shop with 10 - 100 transaction a day.
It seems that bitcoin is not suitable for large scale # of transactions.
A lot of businesses use BitPay:
https://bitpay.com/ (an alternative would be
https://walletbit.com/ ) Especially because most businesses cannot risk for the Bitcoin price to go down and potentially lose dollars ("volatility risk".) But BitPay would probably solve "your" problem too? Obviously there is a fee involved (0.99% I believe - which is at least smaller than 3-4% of PayPal/creditcard.)