I like the UI, it really is a breath of fresh air, in a very dull environment, google has been the same for 8 years, yahoo and MSN are getting more and more crappy ads and "things they think i would like to have on a search page" and then the results are all the same green white and blue! Do they have search.css floating around somewhere...
The name, hello what is google, think 9 years ago, who knew what google or yahoo was, names have to be different and unique, people remember them and don't confuse them with something else. I will admit cuil pronounced cool, is a bit confusing, but it is a name and people will catch on.
As for the results I am very disappointed, like was mentioned the algorithm is not the usual candidate, on their site they mention, it ranks according to relevance rather than rank, which makes sense only if their measure of relevance is any good, the picture thing is also very confusing...
With google when you search for 2 independent search terms, for example I searched for two electronic components not necessarily related but both are components, cuil said no results found, niks Nada nothing. on google the very first result was one from a site which I found all the info I needed and teh ten thousand other results, im sure had some relevance. When i entered the two terms in quotes, google gave me a warning saying, we found nothing in quotes, but here are ten thousand results where they are not next to each other... and again the best result was first. So Cuil needs to work on their algorithm and some parts of the UI the picture thing, but i think it is a move in the right direction.