I came to know from their site that "Cuil is an old Irish word for knowledge"
1. Search Result looks like a news site. This is not a complaint :) May be I am used to the search results page template used by Google, Yahoo, Microsoft. But I like this Cuil result template as well.
2. As usual I tried searching for my name ('Vadivel') and found that Cuil wasn't able to find my blog (atleast it was not available within the first two pages) whereas Google was able to show my blogspot in the first page itself. I even tried changing the search string as Vadivel Blogspot still it wasn't able to pickup!
3. If a search string has multiple meanings they provide those options as a menu style. For ex: Find attached the screenshot which I took by searching SQL
4. Explore by category option also seems to be cool!
Overall the presentation of the result is impressive but accuracy of the results aren't that satisfactory. So i feel its too early to say Cuil is a Google killer!