Canadian Tire bike: Super Cycle Gravity

Hi all,

Candian Tire stores are offering SuperCycle Gravity bikes, which have
features such as front disc brake and full suspension at the attractive
price of Cnd $300. Has anyone tried these bikes? Is it a durable bike?
Are there any other (better known) bikes with these features in this
price range?

Here is the link (hope it works):
http://www.canadiantire.ca/assortmen...=1079771735801

I am also wondering if one can get a bike with dual disc brakes and full
suspension in this price range. Would someone be able to recommend an
online store or forum for buying discounted or second hand mountain
bikes in Canada?

Cam