The three are peer schools academically. The decision should come down to cost and which your child likes best.
Muhlenberg has that very Pennsylvania work hard, play hard feel tempered by the fact the theatre presence is very large. It has a lot of nice attributes and a very nice campus. The food is also excellent.
Clark is a nice school too but it is not as well rounded academically, socially and doesn’t have an athletic culture the way Muhlenberg does.
Of the two, Muhlenberg is more compelling all things considered.
I don’t find comparing the minutiae of the physics departments to be very valuable in this case. Your child still has to like studying and living there.