I see that the OP is in Canada.
Here in the USA I've bought a number of Dells from their "Small Business and Home Office" on-line subsection. They might not have been the absolute cheapest, but they have never failed. (Knock on wood.) Something that gives me some confidence is that this subsection of Dell includes Next-Business-Day-On-Site-Service for one year at no extra charge. Maybe that is also their policy in Canada.
As for Gateway - my memory says that Gateway bought eMachines to learn their tricks of building the absolutely cheapest CPs. Eventually ACER bought Gateway. Don't they still market all three brands?