Blind Study Finds Google Really Does Offer Best Results, by Nov 21st:
Google offered the overall most relevant results for 41% of searches, Yahoo Search for 33%, and MSN Search trailing behind with only a 27% most relevant share.
As of, Novemeber 26th the results were very similar: Google 42%, Yahoo 32%, MSN 26% (see graphic). This is a nice idea. I think it would be improved if more results were shown (only 3 were shown for each search engine). I am also a bit unclear on if it keeps the same letters for each search you do. The results were very close for the searches I tried.
One other note is the display of the results at the search engine naturally effects people's opinion. MSN and Google were showing 3 ads above the results for each search I tried while Google showed none above (or 1 above in one case). So I can believe Google gets an extra bump in real life practice due to the better display they provide users. I also believe Google used to have much more superior results than they do now. I think MSN and Yahoo have improved and Google has gotten worse (I imagine due to concetrated effort by those attempting to fool Google into showing less valuable results higher in the returned list than they would without the extra effort put into fooling Google.