Im going to Canada with my partner with a working visa valid for a year, im unsure about which city to live in.
Work-wise, which places have a greater number of opportunities?From what I've been reading Vancouver has more crime than Toronto, is there a discernable difference?

Vancouver does have more crime, but all in all is a better city to live in. The weather is nice (winters mostly consist of non-stop rain), but at least you're not up to your waist in snow like in Toronto. Work wise Toronto is better as it is home to almost all the companies operating in Canada at the moment. Toronto (and area) is where the food is produced, where cars are made, where beer is brewed, where financial companies and banks call their "home office." But Vancouver has many branches of the same companies, so getting a job, if you're qualified, should not be too hard in either Vancouver or Toronto. The only drawback of Vancouver is that its a little more expensive than Toronto...just a little. Anyway, go to Vancouver for the mild climate and beautiful scenery and go to Toronto for the hub of business in Canada. The choice is yours, I myself prefer:

Vancouver.

I prefer Vancouver.
If you are only going to be here for a year, I would definetly urge you to go to Vancouver. I just moved out here from Alberta, and love it so far.

Getting a job took a little while, but I was very picky.

As for crime, as long as you know to stay off of the Downtown eastside, and away from Surrey, you should be fine.

The amazing scenery, and beautiful city make up for any crime problem that there might be.