My 180 day was this past Sunday! I got out of bed at 5:45 AM and was booking my dining reservations by 6:03 AM online. It worked great.
If you plan to do online booking, I recommend logging into Disney's webiste before Sunday, and making sure your user account works, make sure you remember your password. It also helps to link up your user account to your current resort reservation using your confirmation number. Familiarize yourself with the dining reservation search engine and how it works. Once all of that is set, it will be easier to get on Sunday morning and get down to business.
I got all of my reservations except Coral Reef because 4 or 5 Epcot restaurants are "not released" for reservations yet due to the Candellight Processional. If you plan to eat in Epcot, I would have a plan B and C picked out prior to Sunday.
I got an Ohana dinner (6:40), Chef Mickey for dinner (5:35), CRT for lunch (12:55) and Tusker House for breakfast (8:05). Basically everything I wanted at the time I wanted it.
I called at 7:10 or so (to give the people who didn't use the online reservation system a chance to get in there first) to see what was up with Coral Reef, and to make sure that all of my online reservations were successful. They were!!
I'm certain you'll have equally good luck.