It all comes down to personal tastes in women. There's a much different demographic to choose from in Montreal and to a lesser extent Toronto than there is in Vancouver. There's virtually no ebony providers in Vancouver, for instance, but many asian and south asian providers. Caucasian providers abound in all cities, but if you like latinas you're going to be better off in Montreal. Toronto has a great mix but prices are relatively high and access can be a bit of a struggle at times. The OP says "place to meet SPs", which I'm interpreting to mean let's leave the other city difference aside, so if that's the case then I'm going to go with Vancouver. Provided you like asian SPs in addition to the usual agency/indy/MP dynamic that you get in Montreal there's also a pretty robust network of micros and a collection of "semi-providers" like nail salons that offer the occasional massage, for example. If you step into the micro and semi network then prices are generally lower too, although it can be a bit of a wild west as far as consistency is concerned and every photo is fake. Once you learn how to get around you isolate the better ones. Immediate gratification is much easier in Vancouver than in Montreal and appointments are frequently not needed. Prices are better too, but reviews can be less reliable due to frequent turnover, which is both good and bad. If you don't like asian providers though then I think you'd find yourself a bit starved for choice.
I have no opinion on Ottawa, but Calgary is pretty much a graveyard.