Having been here many, many times, we were gutted 3 years ago when the place closed. About 2 years ago it reopened, under new management, a catering company.
If you are going by old guidebooks (like Fred Plotkin's Italy for teh Gourmet Traveller) you should be aware of this change.
Ranucci still has teh best view in town- the terrace is spectacular with fantastic views of the town and countryside. However, that for me is the only reason now to come here. If you can't sit on the terrace (in winter, because it's full) I wouldn't bother, as there is better food, at better prices, in several other places in town.
The last time I was here the dishes were mostly classic- nothing imaginative, and not worth the hefty price tag.