I was born and raised in Northern Alberta, where "the City" was Edmonton. I also attended my post secondary education there. I also lived in Calgary for a decade, and spent a fair amount of time there for the decade prior to my move. I won't claim to be completely impartial but I can be reasonably objective.
Job markets - as far as I know, prospects are strong in both cities, although more corporate HQs, especially related to the energy sector, are located in Calgary
Traffic - in my experience, Calgary has a better system of roads but the city seems more spread out, because it is more elongated, whereas Edmonton is more circular. The end result is although you may be able to cruise along, on the whole you will have to drive farther in Calgary for anything that is not located in your immediate vicinity. Calgary has a decent transit system, but so does Edmonton, and commutes just seem shorter in Edmonton because of the city's geography.
Rent, I can't comment on. Real estate in Calgary never seems to go down though. Edmonton's real estate market (from what friends/family relate) isn't as explosive but still strong.
Things to do - depends on what you're interested in. Both cities have a lot of ammenities. Edmonton has better shopping and the cultural perks of being the provincial capital, while Calgary is closer to the mountains. Calgary's airport has better and more connections if you want to travel or have friends/family that are farther away. Both cities have a lot on the go.
Weather - again a personal preference thing. Edmonton gets colder. Calgary is dryer. Also, Calgary's elevation and the speed that some weather systems can move through can wreak havoc on some people, especially those with narrower nasal passages or allergies that make them more prone to being congested (I suffered through them and at times the headaches were NASTY, with very little you can do). If the barometric pressure changes don't bother you, you don't have to shovel nearly as much snow in Calgary, as it usually melts within a couple days, except during the coldest snaps of the winter (which are generally shorter and warmer).
If I was to move back to either, my choice would be Edmonton, with the 2 main factors being that I have more friends/family in the North than the South, and the way the weather gave me intense headaches in Calgary... but thats just me
