Biases: I'm a PGY-1 at Northwestern.
NWU vs UChicago:
Call schedule: UChicago wins, for the moment. On the other hand, we are expanding our classes at NWU from 18 to 21. There was some unhappiness with the call schedule a few years ago because one class had dropped from 18 to 14 b/c people left for reasons unrelated to the program (mostly family stuff). The classes that are full seem happy with the schedule.
Caseload: NWU wins. 35 ORs downtown, another 16 or so at Children's Memorial, and a bunch more at Evanston. Tons of regional, tons of sick OB, 4 months of dedicated peds months, tons of cardiac (one of our cardiac surgeons did leave recently but 1) he sucked and 2) he will be replaced very soon). Try asking UoC's program director about his caseload. You will not find a more defensive guy on the interview trail.
Patients: I don't know where this "rich healthy patients go to NWU, poor patients who never see a doctor go to uchicago" meme got started, but it is utter bulls h i t. Just came off a month of wards, where everybody was sick as s h i t, and half of my patients were homeless and/or free care. Nobody going to the OR gets away from having an anesthesiology resident on the case (unless it's a chip-shot case, in which case a CRNA might do it). Speaking of which...
Relations with CRNAs: very cordial at U of C, as far as I could tell. At NWU, CRNAs stop work at 3 pm (!) and guess who replaces them...attendings! OK, usually it's residents, but it's not unusual to see a few attendings a day with their own rooms...there's just that much work to go around.
Categorical internship: NWU. NWU's is harder but you're taking care of sicker patients -- U of C's involves a number of relatively cush months at a community hospital. NWU's is also 10 months long -- you start anesthesia in May of your intern year ahead of your counterparts starting in July.
ICU training: I'm calling this a toss-up. U of C anesthesia covers the CVICU and burn ICU. U of C residents were enthused about burn ICU being an easy month more than anything else -- I'm sure CVICU there is tough and a good educational experience. NWU covers the neurosurg ICU and is in the process of taking over the CVICU. Neurosurg ICU is rough. At the moment, PGY1s and PGY4s rotate through the CVICU with an attending but the CT surgeons and their fellows are calling the shots with NPs (!) doing the grunt work -- we're basically there on a consult basis and for lines, tubes, and other associated bitch-work. Next year, we will have more residents there and the PGY4s will start taking overnight call with (or maybe instead of?) the CT surg fellows. Eventually, the CVICU will function just like the NSICU (surgeons admit to the unit, and then we run the show). Growing pains at the moment though.
Moonlighting: UChicago. NWU doesn't have moonlighting at all, and has no plans to change this.
Didactics: probably U of C.
Location, facilities, ancillary staff: NWU.
Job and fellowship opportunities after residency: tossup
Sorry for the long post; hope it helps somebody.