The restaraunt at the Charles Inn was excellent. Moderately high end, but enjoyable.
Zees (at the Shaw Hotel) is worth skipping - but the hotel itself is excellent.
No other opinions on places to eat, but we loved NOTL. If you are up for it, rent a bike and ride down along the Niagara River and visit some of the wineries (Reif, Iniskillen and Peller are all there). Wonderful way to spend an afternoon.
If you are into wine, make sure to ask for some Wine tasting vouchers at your hotel...Peller gives them out to most.
Have fun...