E-Commerce Shopping Cart ASP Alternatives

We're a long-time customer of Toronto-based 1ShoppingCart.

However, from a business continuity standpoint, it concerns
us greatly that we've been unable to find any worthy
competitors (e-Commerce shopping cart ASP alternatives).

Please provide a list of the top 5 competitors to
1ShoppingCart and the pros/cons of each.

Please also be aware that 1ShoppingCart markets its services
under literally dozens of different private label names,
which really wouldn't help us. We need to locate 5
competitors that run on entirely different technology
platforms.