If you're a legitimate retail business or merchant, I'd think you want to be able to track your payments easily, so why not Coinbase or Bitpay?  I'm sure they have analytical tools and you can see all sorts of statistics on your customer base, so the % they take is well spent.

If you decide just to email your customers a link each time they want to buy something, you'd have to generate a new BTC address or new QR code each time which is pretty inconvenient on your end, or they'll be able to check your available wallet funds.