The tech-savvy -- like those who navigate (and lurk) forums easily -- generally prefer Google ... at least in my experience.
But people like my 60-something parents use IE with the MSN home page left as default. They've HEARD of Google, but they don't USE Google.
And if I changed the default page to Google, my mom would call and ask me where all the news headlines went.
Microsoft has just purchased a company that does mobile search. To be honest, I have not used MSN Search in a long time and I really don't know many people who do. Whenever someone says to search something, they aways say "Google it". Or, "Google it yourself ___"