We went to NF a few years ago. I think our hotel room was about $60 through priceline.com or something. (Boyfriend paid, so I am not exactly sure how that worked.) We stayed on the Canadian side. I don't recall having much trouble getting over the border, it didn't really take that much time. The falls were spectacular! We went in October, but it really wasn't that cold like I had thought it would be. You have to eat at the Skylon restaurant!! It is seven hundred + feet up in the air. You ride up in an elevator, and once you are at the top, it slowly revolves. I was kinda queasy at first, because I don't like heights, but it moves so slowly it wasn't a problem after a few minutes. We went at sunset, and the view was stunning. The food was sooo good! They turned on colored lights under the falls once it was dark, and it was really pretty. And you absolutely must
SEE THE BUTTERFLIES!!! The butterfly conservatory was awesome! It is pretty touristy, but Clifton Hill has a lot of things to do. Fun houses, a Hershey's store (got a super giant candy bar for my dad, he loved it!) an MGM store, etc. We also went over to the American side, for one afternoon. I didn't think the falls looked as big. We went to the aquarium that is somewhere in that area, I can't remember exactly where. I think both sides have a lot of things to see and do, so no matter what you decide, you will have a great time!!
http://www.niagaraparks.com/garden/butterfly.php
http://www.foodinc.ca/9053562651
http://www.cliftonhill.com/