A 2 bedroom has a full kitchen, 2 separate bedrooms (king, queen, pullout) plus a pullout in the living room, the garden suite has 1 bedroom (king) plus a pullout downstairs. 3 TV's in a 2 bedroom vs 2 in a garden suite.
I think a garden suite is only for 4 people (2 in king, 2 in pullout), a 2 bedroom is for up to 8.