My experience is based mainly on connecting from Las Vegas to Vancouver.
There is NEXUS, which is obviously a huge plus. There were 3 machines (although one was out of order).
Bathrooms just outside baggage claim are clean and lots of room.
The part i really don't like is the baggage transfer system. I hate that i have to pick up my bag, bring it 30 feet to another person, who just puts it on another conveyor. Then, you exit out back into what is basically arrivals with no real instruction that you have to basically start from the beginning. Signage is terrible.
Security is a bit more chill here than in Vancouver and Toronto. I had a big bottle of perfume that i bought in Duty Free. It wasn't sealed, but they still let it through.
Maple Leaf Lounge is just past security. I found it to be a bit untidy. Staff was a bit slow to clean up around the TV's. I ended up doing it myself as i wanted to sit down, but 6 seats all had empty drinks.
A number of the other restaurants were closing when i got into the area, so can't really comment on those.
Now that I have been through it once, and know how to connect a bit better, I think I would use Calgary as a connecter hub. If you have NEXUS, you can zip right through.