There are no formal reviews of Georgetown Medical Insitute High School Summer program but there is a review by a student who took a course at GMI for post-bac students wanting to enter med school. His/her impression was positive,  found it very helpful in preparing him/her to apply and enter med school:

The GMI instructor, Carlos  A Suarez-Quian is a professor and has a fairly impressive CV although a bit outdated. He also has a fair few number of publications:

I also note that the blogs listing medical summer high school programs don't include Georgetown - it may/may not be an indication of quality: 
    blog.prepscholar.com/medical-programs-for-high-school-students

 2009