Okay, so this is a little odd, but I did a search and found nothing, and figured that a little advice for searchers is better than none at all. Certainly, it's not a good place to go just for food; on the other hand, if you're there, you often don't want to travel offsite for food. I just completed a brief stay (nothing too bad - I'm feeling much better now) and here's my capsule reviews:
Going from north to south along the hospital's main axis, your dining options are:
Club MEDibiles (Health Sciences Centre). This is in the U of C part of the building; I didn't try anything, but it didn't offer anything particularly tempting. I assume it's open mostly during class hours. It's not worth a detour, but I can't say that the fare anywhere else is worth the trip from the Health Sciences end, either.
(This is where Emergency and admitting are on the main axis; a long way from Club MEDibiles)
Good Earth Cafe (Main Building lobby). Seems to be a standard Good Earth Cafe. I personally never cared for the tea they offered; the Earl Grey wasn't Earl Grey-y enough, if you know what I mean. The baked goods selection is better than the hospital-run places. I think it closes 10 PM.
Timberline Cafe (ground floor, between Main and Special Services). First, a few words about how to find this place. These other places are all on the main floor, which is the floor you enter when you come in off the road. This one is located one floor down. When you're walking south on the main axis, past the main building lobby, you come to an area where stairs lead down to a sort of two-story atrium off to your left; there's a lot of plants there. The Timberline is down the stairs and back to the north a bit. It's the biggest room, and seems to be more for the hospital staff than the others. It does three meals, but isn't open too early or late. Rotating daily selection of food; one day there was an awesome smelling BBQ pre-formed rib patty that I regret not trying, and an old heatlamp pizza I regret trying. This place does a couple of more cafeteria-style entrees, and I think it does a sandwich station sometimes as well. Pizza is available, but they cook the new one once the old one is gone, so don't buy the last slice. I personally preferred the standard Tazo tea here to the Good Earth's stuff.
Garden Cafe (Special Services Bldg). This is probably your best bet, as long as you want one of the few things they do well. They run 24 hours (save two quick cleaning periods) and do breakfast until 10:45. The main attraction here is a grill; they do the standards (bacon and eggs, hamburgers) and despite being in a hospital, have an operating deep fryer. One of the best things is that they aren't really well suited to produce volume, which means that anything deep-fried winds up being served absolutely fresh. The fries aren't the best I've ever had or anything, but I've had a lot worse a lot of places. I couldn't bring myself to order poutine in a hospital, but I probably missed out. Prices aren't ridiculous; one nice thing is that they do breakfast piece by piece; one morning, my cold cereal and muffin didn't quite cut it, so I ran downstairs and added three slices of bacon and a hash brown triangle for only $2.25. There's also some standard pre-made salads and sandwiches and the usual suspects in the drink and baked goods line. I never checked out the baked goods in the morning; by the evening, the selection was pretty threadbare; a lot of bran muffins. For what it's worth, the baked goods that were brought to my bed each morning were one of the highlights; moist and crammed with stuff, albeit on the small side.
Maybe if you're a coffee devotee, Good Earth is your speed, and if you want an actual meal rather than a fried snack, you may check out Timberline, but you can meet me in the Garden Cafe when you're done. I'll be the guy with the poutine or the white chocolate cranberry scone.