I find that they both get similar results, but sometimes it's worth checking both if I don't find what I'm looking for right off.
I actually use Goodsearch It uses the yahoo search engine and donates a .5 cent to my school every time I do a search. Lots of charities to choose from.
I also use firefox w/ add to search bar. It lets me add custom search bars in my regular tool bar w/ out adding yahoo toolbar or google toolbar or anything else like that. Just right click on the search bar at any website and ''add to search bar'' and it's now in your search engines.