On our first midterm, there were only 4 As in our class of about 40 people. 3 of the 4 As belonged to homeschoolers (myself included). Surprising? I think not.
These stories are heard quite often. I have a son taking his first college classes. English 101 (which he tested into without preparation, after unschooling) isn't going as well as the math, but he's like his dad, who also had some English 101 problems, after 13 years of public school.