Update 10/20/08 application was removed from app .store.
I use the OpenTable online reservation system fairly frequently and have found that using their standard or mobile web sites in Safari is clumsy . If I know the restaurant I want to reserve, there is no issue. However if I want to browse for a restaurant close to my current location the web site is somewhat difficult to navigate. If you use a PC the OpenTable website works well, it is just not designed for the iPhone or Safari.
The developers of the Restaurant Reservations application realized the issues, and have provided an good alternative to using Safari to browse OpenTable. For $.99, it is worth the price.
There seems to be some confusion between the standard and mobile OpenTable web sites. The Restaurant Reservations application uses the mobile web site. From my support discussion with OpenTable they run those sites on separate systems (they have plans to merge them). The standard web site requires logon credentials while the mobile web site does not. OpenTable matches your account on the mobile web site by using your name, email address and phone number. Once you enter them once, a cookie is created to remember the information on your device. Also the reservations made on the mobile web site are not viewable in the standard web site and vice versa.
The killer function in Restaurant Reservations is the ability to use your current location to find nearby restaurants. It then provides you description information, address, phone number, transit information, and a link to reserve via OpenTable. The application brings up the OpenTable mobile web site for you to complete the reservation. You can then use Google Maps/Directions to find your way there.
It would be nice for reviews to be included, transit directions/time, and links to restaurant web sites. Since the current list of restaurant information is stored locally, I am not sure how the application synchronizes its database to keep it up to date. Hopefully this will be done over the air and not via iTunes...
Just as a note: Zagat also uses OpenTable to make reservations. Their mobile web site www.zagat.mobi provides reviews and links to the OpenTable mobile web site. You must however set your location manually. Zagat does require a subscription to view their reviews, basic restaurant information is free.