I have been delivering business cards , and I am getting a lot better response than when I used to use flyers !
I've found exactly the same!
I built my round using business cards.
Then I had 10,000 colourful glossy flyers printed for ad hoc canvassing and the response to them wasn't very good at all.
I now use business cards again, with my business name, personal name and all contact details listed... I get a much better response!
Andy