Hi,
Niagara Falls the city isn't particularly pretty. Of course you are there for the Falls. However, the Falls are definitely very pretty at night when they are lit with various coloured spotlights.
You might want to look into staying at Niagara-on-the-Lake which is a small town north of Niagara Falls (about 25km). It has a main street that has little shops and cafes and the like (also touristy but different from the more carnival/fair feeling of the falls). There is also a lot of B&B accommodations and various higher end inns in NotL.
The restos in Niagara Falls tend to be on the chain/touristy side so spending the night in NotL would open up your dining options.
I am assuming you will be driving (rental car) and you should keep in mind the traffic between Niagara and Toronto can be quite heavy at times. Weekday rush hours can add an extra hour on that route AND on a lot of weekends there can be a lot of visitor/travel traffic in the corridor between Toronto and Niagara.