[jQuery] selectors

[seo++]

for this form
<form name="f1" method="get" action="/search" id="searchform" >
        <input type="text" name="q" value="Search...." size="70" />
        <input type="submit" value="Search" />
</form>

why
$("#searchform input")[0]
is different than
$("#searchform input:first")

I can get  values for $("#searchform input")[0].defaultValue or .value
but not with .fadeIn() or val() while the reverse for the $
("#searchform input:first")