You probably know that Lehigh has a much stronger STEM orientation than BC. So the options for physics-related study and research are probably going to be much broader at Lehigh, even though BC is about twice as large overall. For example, Lehigh offers undergraduate majors in physics, engineering physics, engineering mechanics, mechanical engineering, astrophysics, astronomy, and materials science & engineering. BC has a major in physics, and that’s it.
On the other hand, BC has a stronger humanities orientation. My guess is that the music and language programs will be significantly larger at BC. And there are probably better opportunities to attend concerts in the Boston area.