Ive built my whole business on leaflets, and have over 350 very well priced custies.
I have 10,000 at a time dropped, and yes some custies are scattered about, but because i price them higher than normal, its worth me doing them, ive got 20,000 going out at the mo.
Results vary, but i find its the best way to build a well priced round, as the customer is calling you, rather than you asking them.
Many will argue other ways are best, but its worked very well for me.