The link which qorax has posted above gives a very good overview objectively / numerically, of the various parameters based on which we can compare different cities in Canada.
With respect to the core topic (Calgary vs toronto), let me take a shot at it subjectively. I have actually stayed in both cities for quite a while (in Calgary for more than a year and in Toronto for a few months ) and this is my 2 cents to answer the OP:
1) Business : Though both the cities are prosperous and trade continues to flourish in them , Toronto is more aggressive in terms of business attitude . You can have a larger network in Toronto than in Calgary obviously because of the diverse population and extremely aggressive business culture . Calgary , as a lot of others have commented is a bit laid back and people there are more chilled out . But it is booming becauuse of its richness in natural resources and the housing prices have sky rocketed over the past decade.
2) Weather / nature: If you are a nature person , Calgary undoubtedly is the best place on earth .The beauty of the Rockies surrounding you is breathtaking . The drive from Calgary to Banff (more than an hour`s drive) is considered to be one of the most scenic drives in the world. If your dream is to ski, then Banff is the place where you want to be ! It gets colder in Calgary (real cold) as compared to Toronto , where the lake Ontario apparently never freezes.So , if you arent a winter person , you might have to face a couple of real harsh months in Calgary . But personally, my experience has been that "when the weather goes beyond -15 , it doesnt really matter whether its -25 or -40".You know what i mean?
3) Family life / entertainment : Toronto is more lively a city than Calgary . As i mentioned earlier , not only can you network better(for business purposes) in Toronto , but you tend to establish personal acquaintances pretty quickly there . Needless to say ,the Indian community is very prevalent there and the sense of community is pretty strong.In Calgary as well, you have a good presence of the Indian community . Have been to a couple of temples there and attended a couple of Dandia functions in Calgary as well
. But obviously, the numbers are less as compared to Toronto.
Overall, it depends on what your prioroties are and what kind of a lifestyle you want to prefer.
My personal favourite is Calgary and i would pick that as I love to ski ,love to spend lesser time on the roads in jams and love nature!