MODERATOR’S NOTE: Please stick to the OP’s question. This thread is not supposed to be a general discussion of ED.
It sounds like the OP does want NU, but has a really good offer from Loyola. If NU accepts OP, with a good FA offer, OP will go to NU. If not accepted or accepted without enough aid, OP goes to Loyola.
NU set up the conditions and timing of ED. If NU wanted first crack at all ED applicants, they could move the ED timeline up. NU could give more aid. NU is in control of this situation.
A lot of this will depend on your major, what kind of FA you get, and what you want to do after undergrad. Without these, it’s hard to answer the question. If you get decent FA say and want to major in journalism, then it’d be hard to turn down Northwestern, if you want engineering and a job in the Chicago area or midwest, Loyola may be better. If you’re thinking about grad school, Loyola could be better as you can use the money saved for that.
^NU has a pretty good engineering program too and a few disciplines are highly ranked.
OP, unless you are trying to get into top consulting firms for which NU is a heavy target, you are better off taking the full ride (assuming you don’t qualify for much aid from NU). Most employers in other fields are not as prestige obsessed and you would be the big fish in a smaller pond at Loyola. Your path in those fields is really all about you, rather than which school you attended.
Hard to beat free.