I just tried to make a reservation at Mistral and saw that only the off-peak times are open, like 5:30 and 9:30 so I called. Apparently peak-time RW reservations are only open to American Express holders until this Friday the 19th, at which point they will be open to the rest of us.
Toro is a good deal, especially as RW is the only time they take reservations. The RW menu is just the regular menu, with a set number of selections per person (I seem to recall it being about 2.5 tapas + 1 pincho + churros per person). I had a good time at Harvest in Harvard Square last year, and at Mama Maria in the North End.
Generally speaking my feeling is that it is only worthwhile as a way to try restaurants that are normally very pricey. Sure, you'll be getting a limited menu, but at a place with entrees that are normally $35+, Restaurant Week is an affordable way to get a taste of the experience and what those restaurants have to offer.
I have a few Restaurant Week questions too, if anyone can help.
1) Do more restaurants come on board later or is the current list complete?
2) Do I just go ahead and reserve on the OpenTable links next to the restaurant list? If so, are all reservations at that time RW reservations?
3) Anything else a RW newbie should know?
I think the list is pretty complete, menus will be added as time goes on. Usually you can order off the regular menu too if you go during RW. I always go for restaurants that are fairly pricey during normal times, no need to go to Metropolis where entrees are <$20. Have had some recent good RW meals at Oceanaire, Marco, Bistro 5.