I have worked in the university “industry” for about 20 years and your son has some great options before you. Here are some additional thoughts that might be helpful or might add to your confusion (I hope not the latter). The poster who asked what a grad would make in 10 - 20 years after graduation is asking a great question.
However, all your options will produce good starting salaries and job choices. It is not easy to predict what engineering positions will be like with 10-20 years experience and most people make significant career changes in that period of time. Consider what your resume will look like in 10-20 years. The Harvard name will glow for the rest of professional career and can open job opportunities in most areas in and outside the engineering profession. If he chooses to become a physician, a diplomat, or a librarian at some future time, the Harvard name will be attractive. People the world over recognize the name. Every day I benefit from having a college name on my resume that is universally respected. It is hard to quantify but it is valuable.
Second, consider who you are in class with. At each school you will be studying with very very bright students. The atmosphere and performance level of your peers will drive much of the experience of getting at degree at any of these institutions. Of course, the students in engineering will have a different discipline and culture than those in other fields of study. You can’t meet them and know who will be your friends till you arrive for study—you can only know they will be very smart and hard working.
Your reply strikes at the heart of many of the issues and concerns about which we're thinking.
When I went to college, I chose the school to which I was accepted that had the best reputation in my major field, not the school with the best all-around reputation. I dropped out of that major field before completing grad school, and am now in a completely different field.
I always thought that, given my career path, it would have been more helpful to have graduated from the school with the somewhat more recognized and prestigious “brand name.”
As well, I made no life-long business connections in college. Just wasn't that sort of student body. That's Harvard's “Rolodex advantage.”
But Maryland is a better school for engineering, and the university has made it very, very attractive for him to go there. As well, they have added something to his scholarship package that at least partially makes up for Harvard's “Rolodex advantage.”
You've really nailed some crucial questions. Now I wish we could get the crucial answers! LOL.