I cannot speak for Mont Air.
Both Toronto Airways and Brampton are good. Their equipment and capability are very similar. Brampton is a flying club, and owns it's own airport, which is uncontrolled. It is a little distance northwest of Toronto, and not really close to "town". It tends to have less air traffic, which means you spend more time flying and less time taxiing and holding short. Toronot Airways is at Buttonville Airport at the northeast of Toronto. That airport is more busy, so you often have to wait a bit, but you get lots of radio work! Both have aircraft ond staff of comparible cost and quality, and similar high quality teaching environments.
Pilot DAR