First off, I DID NOT interview at SLU, so I can not say anything about it objectively. I did interview at Wash U.
First reputation you were asking about, no doubt that Wash U has a better reputation nationally as far as an academic center and national leader.
At Wash U on interview day we rounded with team. Very freaking busy, no teaching on rounds, residents sharp as a tack, I saw teamwork. The upper level was very concerned about even distrib of patients. Nice residents. Not the most laid back place.
Wash U has very few months that are not q4 and I think that makes it rigorous.
PD Keating is the nicest guy you will ever meet.
Lunch conference was great, led by a third year, no obnoxious people.
Overall Wash U I think suites someone who gets off on being very busy and learning from brut volume.
Hosptial beautiful, private patient rooms. Doing some expansion of NICU (oh god, more patients)
SLU--again, know nothing about it other than they did not fill through the match last year and talked to a couple of people on the interview trail who said it is definately not in the same league as Wash U.
Hope this helps. I liked Wash U but I feel that I would get burned out there and I need a little more "hand holding" and more personal teaching.
Good luck.