Who got more weight on the streets in Quebec these days? HA. If we're just talking sheer manpower and especially the capability and the "military smarts" to put the manpower to good use, the mafia would get butchered by the bikers in Quebec.
When it comes to infiltrating 'legitimate' instances on the other hand, it's still hard to tell... I don't think the mafia lost a lot of power there.

When we're talking Ontario on the other hand, I'd give the edge to the Calabrian clans. They got both the infiltrative connections as well as the muscle.
The Ontario bikers got muscle, but on an organizational level they're not up to par with their brethren in Quebec and BC.