I’ve been a faithful and generally satisfied Google user for years now. But like many folks out there have found that both Ask and Yahoo! provide a close second, for the search results sought.
Can’t say that I have tried this recently myself, but I do know that both work well enough as alternate search engines in general.
As expected, Bing is just not as “big”, in the results realm as of yet. Likely due to its newness more than anything, there is something to be considered though when Bing is being beat out by a third party search engine like Ask. Both offer about the same level search result, yet despite Microsoft’s ad blitz, Ask wins.