I'm one of the guys from Defcon.
We got a nice group of people playing and best of all its local. When you get your feet wet into Airsoft at Defcon. You should then proceed to TTAC3 which is at downtown Toronto where more of the veteran players play for some extreme CQB. And there are rentals available too.
Brian McIlymoyle is the host of TTAC3 games as well as a co-owner of FAC
Go to TAC3 to learn all about Airsoft. Brian is a great instructor when it comes to learning more about combat techniques and general ways of the road in Airsoft. He also holds teaching sessions for new joiners.