Just tried this service. It was only 58 minutes from the time I placed my order on the pizzaforcoins.com website until the time I had hot, fresh, Domino's pizza in my hands.
Advantages: Easy-to-navigate site; on-screen invoice for easy payment; fast delivery! And an extra +1 because I'm under the weather and don't feel like cooking, and this service came through in the clinch
Disadvantages: A bit pricey (from what I can tell, using this service costs somewhere around $5 USD for "processing fees"). Also, tipping with BTC is still not an option, and it would be nice to see the full, expanded menu.
If three changes could be made to enhance my consumer experience, they would be:
1) Allow tipping via BTC (I saw that you are working on this)
2) Allow the ability to relay a typed message to the delivery driver (e.g. in my situation, I wanted the driver to call upon arrival, but there was no text field for me to request this)
3) Expand the menu selection! No wings?
Also, a bug you might want to fix -- when I attempted to click on the on-screen invoice to submit payment, I was redirected to a new, blank tab instead of being redirected to a payment page. Consequently, I experienced a few minutes of panic between the time that I decided to send payment directly to the Bitcoin address provided on the invoice and the time when payment was confirmed via confirmation email. It might be useful to provide a little warning to let users know that there may be a slight delay in the time it takes to confirm payment, but as long as BTC has been sent to the correct address as provided on the invoice, there is no need to worry. If I'm correct, it seems that you wait for 1 confirmation before confirming the order with Domino's.