Are reservations required or highly suggested?

It's a good idea to make reservations

Always a good idea. They have plenty of days where they get completely booked.

yep, HIGHLY suggested!

I would make reservations... Especially if you have a large party.

We had always made reservations there over the years but I don't think reservations are required. I think this was a better restaurant 20 to 25 years ago. This time the food was only slightly better than average and my wife and I thought the $125 bill (not including tip) was a bit steep. We both had entrees, bottle of wine, and shared one dessert. I probably would have been okay with that if the food was of a better quality.

Suggested, but we had no issues for seating for a late Saturday dinner

not required, but highly suggested....request to eat downstairs, the chairs are more comfortable and it's cooler.

Highly suggested.