I can't say with any certainty, but I don't think the results are as relevant as Google, Yahoo or Live (I don't really know about ask as I haven't used it more than once or twice), but it still looks like the image results are very strange to the point of just being wrong. I wouldn't use Cuil if I was personally looking for anything at all, but I would (and do) use the 3 main ones interchangeably.

I just put in some example phrases that I thought would be no brainer's for any algorithm to work out.

For "TechCrunch" it gives me a Gmail beta image, 2 links to the techcrunch homepage and a link to some conference they had back in April, no mention of Michael Arrington whatsoever.

For "Google" it gives me earth.google.com as the main result but interestingly enough down near the Google Labs link, the image is a picture of a flying monkey (I don't know if anyone else sees this, so I took a screenshot)

For "Yahoo" first result is yahoo's homepage, but the included image is a banner ad.

For "Microsoft" the link to the microsoft homepage's accompanying text is about qbasic for dos. Also interestingly, the image attached to their research labs is the Apple logo, which might say something... screenshotted.

For "Apple" the first result is apple's home page, the accompanying image I can't make out but is definitely un-apple-like... it's a black screen with what looks like the letters "LCA" in gray.

So next stage I'll give it some results which shouldn't be "top tier".

For "Y Combinator" the first result happens to be YC, with the YC logo so grats guys.

For "Warhammer Online" the result links to their homepage, but the attached image is a tiny sponsor image at the footer of the page.

For "Calacanis" it gave me a link to Jason's weblog, the attached image is a pie of some variety. Also interestingly enough the wikipedia entry has the Lost splash graphic.

For "Paul Graham" it seemed like everything works great, Paul's pic is up the top, until down the bottom theres a pic of someone who I can't determine, but it looks like he could have come from the set of a 70's porn film.

Now last phase would be some out there phrases, stuff that would be more difficult for the engine but could be considered relevant to someone who lived in my city. I figure we're the most isolated city on the planet (in terms of distance to anything), so lets see what it could do. For kicks, I turned safe search off.

Since I just did PG, I figured I would throw in my name for laughs, "Mark Lancaster", the very first result I could find even mildly related to me is page 16, which is someone who's befriended me on Digg and shows me on their friends list. My personal blog was on page 22 which they haven't seemed to have visited since mid June. Interestingly enough I just did the same for Google, Yahoo and Live and I was results 4, 1 and 1 respectively.

Something more specific "Perth Bell Tower", a page of pure spam sites.

I typed in a large mining town in our state "Kalgoorlie" that is well known for the amount of gold it produces, the first result for me happened to be about Hay Street which as I just found out is red light district. Interesting.

Ok, something a little more obvious since it doesn't seem to play nice with niche terms, how about "Perth", being the city I live in. All the results point to the town of Perth in Scotland, which has a population of 40,000 people, whereas my Perth is a city with a population of 1.5 million. I followed up with "Perth City" thinking that it might point to the actual city called Perth, and not a town - but still points to Perth, Scotland. Perhaps the results might need tweaking there as I'm sure they don't take location by IP address into account in their algorithms, which many other sites (not just search engines) can manage to do.

I don't think any of the other big 3 have anything to fear just yet, the formatting of the pages are nice, but the results just don't seem to be all that relevant which is a shame and I do hope they fix it.