1. it is a good idea living in Quebec if you belong to the low family income category with 2 or three kids. You don't necessarily pay more tax than you do in Ontario and you have 7/day dollar day care vs $40/day in Ontario. On top of that, each child gets Quebec child assistance as well as Federal CCTB. Plus you and you kids are covered with extensive health care including dental for the children. Of course, there are other things such as free water, cheap auto insurance, cheaper hydro bills and cheaper rent or housing.
Move back to Ontario once your children reach school age because all advantages as a Qeubecers will be disappearing. You don't need $7 day care anymore and you can't get Quebec child assistance anymore either ( age limit 7 if i am not mistaken) and you children have to go to french school (there are exceptions though if you qualify).
2. if you belong to middle to high family income category, stay in Ontario.