There is a stark difference between both universities in terms of culture as well as fees. JNU or Jawaharlal Nehru University is mostly about expression, literature, culture, research, and building intellectual facilities whereas DU is all about glamor, fashion, fests, high cutoffs, and placements.
In financial terms, JNU is much more affordable than DU. Be it course fees or hostel fees, JNU cuts down on expenses a lot.
JNU is learning for life, whereas DU focuses on learning the bare essentials and getting placed in a reputed firm.
One more significant difference to consider is that JNU is more about post-graduation whereas DU focuses more on graduation. The difference in intellectual level stems from the same reason.
If you are still confused between the two, spend equal time on both campuses and you will get the answer soon.