It really surprises me that the other discount stores weren't able to survive there. I hope Dollarama has a winning formula, because it really is a great place for a lot of things (it always amazes me what you can find there for a buck or two).
My kids are super excited about the new Dollarama since they get lots of arts and craft supplies (stickers, crayons, etc.) at great prices.
Dollarama definitely has a winning formula vs. the usual discount shops, to the point that Wal-Mart and Canadian Tire are seeing them as threat in certain impulse and small item categories. Wal-Mart easily killed Bi-Way, but Dollarama is a different opponent entirely.
Where Dollarama is really making its mark is in canned foods, where they are rapidly grabbing share.
A quick summary of Dollarama vs. regular discount shop:
Nicely designed and neatly kept store exteriors (big windows, good view in from street) / old worn out sign out front, no view inside from out
Wider (comparatively), clean, well lit aisles / narrow, dirty, dark aisles
Clean, tiled floors and surfaces / worn lino or creaky wooden floors
Almost all merchandise on pegs for easy view and shop / bulk bins filled with misc goods all over store
New and matching store shelves and fixtures / old second-hand hodgepodge of shelves and fixtures
Helpful (comparatively), uniformed staff / no uniforms (do you work here?) and hit or miss if the owner is helpful
Uniformed security guard (if needed, such as the Sherbourne/Shuter location) / never
Good quality (for discount store), branded, in demand products / hit or miss
Of course these are just my observations, and others may have a different view.
One of my favourite uses for Dollarama is movie night out. Just before I go to the theatre I buy the same giant Glosette raisin box for $1 that Cineplex clarges $4 for.