Google vs Bing results experiments

When you swap the logo of google and bing doing such that when you search on google you get the result of bing and vis versa. It happens that when you ask the users what are the best results most of them say google results which in fact are results from bing. This test was done years before with google and yahoo.
Does google better engineered or just well marketed.
I think marketing did more about the success of google than technology says.